The Geography of Oklahoma encompasses terrain and ecosystems ranging from arid plains to subtropical forests and mountains. Oklahoma contains 10 distinct ecological regions, more per square mile than in any other state by a wide margin.It is situated in the Great Plains and U.S. Interior Highlands region near the geographical center of the 48 contiguous states. Usually considered part of the South Central United States, Oklahoma is bounded on the east by Arkansas and Missouri, on the north by Kansas, on the northwest by Colorado, on the far west by New Mexico, and on the south and near-west by Texas.
Oklahoma is a state in the South Central region of the United States, bordered by Kansas on the north, Missouri on the northeast, Arkansas on the east, Texas on the south, New Mexico on the west, and Colorado on the northwest. It is the 20th-most extensive and the 28th-most populous of the fifty United States. The state's name is derived from the Choctaw words okla and humma, meaning "red people". It is also known informally by its nickname, "The Sooner State", in reference to the non-Native settlers who staked their claims on land before the official opening date of lands in the western Oklahoma Territory or before the Indian Appropriations Act of 1889, which dramatically increased European-American settlement in the eastern Indian Territory. Oklahoma Territory and Indian Territory were merged into the State of Oklahoma when it became the 46th state to enter the union on November 16, 1907. Its residents are known as Oklahomans, and its capital and largest city is Oklahoma City.
An ecoregion is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than an ecozone. All three of these are either less or greater than an ecosystem. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural communities and species. The biodiversity of flora, fauna and ecosystems that characterise an ecoregion tends to be distinct from that of other ecoregions. In theory, biodiversity or conservation ecoregions are relatively large areas of land or water where the probability of encountering different species and communities at any given point remains relatively constant, within an acceptable range of variation.
The Great Plains is the broad expanse of flat land, much of it covered in prairie, steppe, and grassland, that lies west of the Mississippi River tallgrass prairie in the United States and east of the Rocky Mountains in the U.S. and Canada. It embraces:
The state has four primary mountain ranges: the Arbuckle Mountains, the Wichita Mountains, the Ozark Mountains and the Ouachita Mountains.Part of the U.S. Interior Highlands region, the Ozarks and Ouachitas form the only major highland region between the Rocky Mountains and the Appalachians.
The Arbuckle Mountains are an ancient mountain range in south-central Oklahoma in the United States. They lie in Murray, Carter, Pontotoc, and Johnston counties. The granite rocks of the Arbuckles date back to the Precambrian Eon some 1.4 billion years ago which were overlain by rhyolites during the Cambrian Period. The range reaches a height of 1,412 feet above sea level. According to the U.S. Geological Survey (USGS):
The Arbuckles contain the most diverse suite of mineral resources in Oklahoma: limestone, dolomite, glass sand, granite, sand and gravel, shale, cement, iron ore, lead, zinc, tar sands, and oil and gas; all these minerals are, or have been, produced commercially.
The Wichita Mountains are located in the southwestern portion of the U.S. state of Oklahoma. It is the principal relief system in the Southern Oklahoma Aulacogen, being the result of a failed continental rift. The mountains are a northwest-southeast trending series of rocky promontories, many capped by 500 million-year old granite. These were exposed and rounded by weathering during the Pennsylvanian & Permian Periods. The eastern end of the mountains offers 1,000 feet (305 m) of topographic relief in a region otherwise dominated by gently rolling grasslands.
The Ouachita Mountains, simply referred to as the Ouachitas, are a mountain range in western Arkansas and southeastern Oklahoma. They are formed by a thick succession of highly deformed Paleozoic strata constituting the Ouachita Fold and Thrust Belt, one of the important orogenic belts of North America. The Ouachitas continue in the subsurface to the southeast where they make a poorly understood connection with the Appalachians and to the southwest where they join with the Marathon area of West Texas. Together with the Ozark Plateaus, the Ouachitas form the U.S. Interior Highlands. The highest natural point is Mount Magazine at 2,753 feet.
A portion of the Flint Hills stretches into north-central Oklahoma, and in the state's southeastern corner, Cavanal Hill is officially regarded as the world's tallest hill; at 1,999 feet (609 m), it fails the definition of a mountain by one foot. More than 500 named creeks and rivers make up Oklahoma's waterways, and with 200 lakes created by dams, it holds the highest number of reservoirs in the nation. Oklahoma covers an area of 69,898 square miles (181,030 km2), with 68,667 square miles (177,850 km2) of land and 1,231 square miles (3,190 km2) of water, making it the 20th-largest state in the United States. Generally, it is divided into seven geographical regions: Green Country, or Northeast Oklahoma, Southeastern Oklahoma, Central Oklahoma, South Central Oklahoma, Southwest Oklahoma, Northwest Oklahoma, and the Oklahoma Panhandle.
The Flint Hills, historically known as Bluestem Pastures or Blue Stem Hills, are a region in eastern Kansas and north-central Oklahoma named for the abundant residual flint eroded from the bedrock that lies near or at the surface. It consists of a band of hills stretching from Kansas to Oklahoma, extending from Marshall and Washington Counties in the north to Cowley County, Kansas and Kay and Osage Counties in Oklahoma in the south, to Geary and Shawnee Counties west to east. Oklahomans generally refer to the same geologic formation as the Osage Hills or "the Osage."
Cavanal Hill, located near Poteau, Oklahoma, is billed by a local chamber of commerce as the "tallest hill in the world" because the elevation of its summit is 1,999 feet (609 m). The actual summit elevation is 2,385 feet (727 m) above sea level; the difference in elevation between the summit and the Poteau River 3 miles (5 km) to the north is 1,960 feet (600 m).
Green Country, sometimes referred to as Northeast Oklahoma, is the northeastern portion of the U.S. state of Oklahoma, which lies west of the northern half of Arkansas, the southwestern corner of Missouri, and south of Kansas.
Situated between the Great Plains and the Ozark Plateau in the Gulf of Mexico watershed, feet (1,516 m) above sea level, situated near the far northwest corner of the Oklahoma Panhandle. The state's lowest point is on the Little River near its far southeastern boundary, which dips to 289 feet (88 m) above sea level.Oklahoma tends to slope gradually downward from its western to eastern boundaries. Its highest and lowest points follow this trend, with its highest peak, Black Mesa, at 4,368
The Gulf of Mexico is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. The U.S. states of Texas, Louisiana, Mississippi, Alabama, and Florida border the Gulf on the north, which are often referred to as the "Third Coast", in comparison with the U.S. Atlantic and Pacific coasts.
Black Mesa is a mesa in the U.S. states of Colorado, New Mexico, and Oklahoma. It extends from Mesa de Maya, Colorado southeasterly 28 miles (45 km) along the north bank of the Cimarron River, crossing the northeast corner of New Mexico to end at the confluence of the Cimarron River and Carrizo Creek near Kenton in the Oklahoma panhandle. Its highest elevation is 5,705 feet (1,739 m) in Colorado. The highest point of Black Mesa within New Mexico is 5,239 feet (1,597 m). In northwestern Cimarron County, Oklahoma, Black Mesa reaches 4,973 feet (1,516 m), the highest point in the state of Oklahoma. The plateau that formed at the top of the mesa has been known as a "geological wonder" of North America. There is abundant wildlife in this shortgrass prairie environment, including mountain lions, butterflies, and the Texas horned lizard.
The Oklahoma Panhandle is the extreme northwestern region of the U.S. state of Oklahoma, consisting of Cimarron County, Texas County and Beaver County, from west to east. As with other salients in the United States, its name comes from the similarity of its shape to the handle of a pan.
Most of the state lies in two primary drainage basins belonging to the Red and Arkansas rivers, though the Lee and Little rivers also contain significant drainage basins.In the state’s northwestern corner, semi-arid high plains harbor few natural forests and rolling to flat landscape with intermittent canyons and mesa ranges like the Glass Mountains. Partial plains interrupted by small mountain ranges like the Antelope Hills and the Wichita Mountains dot southwestern Oklahoma, and transitional prairie and woodlands cover the central portion of the state. The Ozark and Ouachita Mountains rise from west to east over the state's eastern third, gradually increasing in elevation in an eastward direction.
A drainage basin is any area of land where precipitation collects and drains off into a common outlet, such as into a river, bay, or other body of water. The drainage basin includes all the surface water from rain runoff, snowmelt, and nearby streams that run downslope towards the shared outlet, as well as the groundwater underneath the earth's surface. Drainage basins connect into other drainage basins at lower elevations in a hierarchical pattern, with smaller sub-drainage basins, which in turn drain into another common outlet.
The Red River, or sometimes the Red River of the South, is a major river in the southern United States of America. It was named for the red-bed country of its watershed. It is one of several rivers with that name. Although it was once a tributary of the Mississippi River, the Red River is now a tributary of the Atchafalaya River, a distributary of the Mississippi that flows separately into the Gulf of Mexico. It is connected to the Mississippi River by the Old River Control Structure.
The Arkansas River is a major tributary of the Mississippi River. It generally flows to the east and southeast as it traverses the U.S. states of Colorado, Kansas, Oklahoma, and Arkansas. The river's source basin lies in the western United States in Colorado, specifically the Arkansas River Valley, where the headwaters derive from the snowpack in the Sawatch and Mosquito mountain ranges. It then flows east into the Midwest via Kansas, and finally into the South through Oklahoma and Arkansas.
Oklahoma had few natural lakes. Those that did exist were either oxbow or playa lakes. Oklahoma has sixty-two oxbow lakes above 10 acres (0.040 km2) in size. The largest, near the Red River in McCurtain County is 272 acres (1.10 km2). The prolonged drought that started in 1930 and created the condition called the "Dust Bowl", led to the construction of a great many reservoirs throughout the state. Now, Oklahoma has the largest number of lakes created by dams of any state in the United States, with more than 200.
McCurtain County is located in the southeastern corner of the U.S. state of Oklahoma. As of the 2010 census, the population was 33,151. Its county seat is Idabel. It was formed at statehood from part of the earlier Choctaw Nation in Indian Territory. The name honors an influential Choctaw family that lived in the area. Green McCurtain was the last chief when the Choctaw Nation was dissolved before Oklahoma became a state in 1907.
The Dust Bowl was a period of severe dust storms that greatly damaged the ecology and agriculture of the American and Canadian prairies during the 1930s; severe drought and a failure to apply dryland farming methods to prevent the aeolian processes caused the phenomenon. The drought came in three waves, 1934, 1936, and 1939–1940, but some regions of the high plains experienced drought conditions for as many as eight years. With insufficient understanding of the ecology of the plains, farmers had conducted extensive deep plowing of the virgin topsoil of the Great Plains during the previous decade; this had displaced the native, deep-rooted grasses that normally trapped soil and moisture even during periods of drought and high winds. The rapid mechanization of farm equipment, especially small gasoline tractors, and widespread use of the combine harvester contributed to farmers' decisions to convert arid grassland to cultivated cropland.
Forests cover 24 percent of Oklahoma,and prairie grasslands, composed of shortgrass, mixed-grass, and tallgrass prairie, harbor expansive ecosystems in the state's central and western portions. Where rainfall is sparse in the western regions of the state, shortgrass prairie and shrublands are the most prominent ecosystems, though pinyon pines, junipers, and ponderosa pines grow near rivers and creek beds in the far western reaches of the panhandle. Marshlands, cypress forests and mixtures of shortleaf pine, loblolly pine, sabal minor, and deciduous forests dominate the state's southeastern quarter, while mixtures of largely post oak, elm, cedar and pine forests cover the Ozark Mountains in northeastern Oklahoma. Many rare, relic species such as sugar maple, bigtooth maple, southern live oak, and nolina inhabit Southwestern Oklahoma and the Wichita Mountains.
The state holds large populations of white-tailed deer, coyotes, bobcats, elk, and birds such as quail, doves, cardinals, bald eagles, red-tailed hawks, and pheasants. In prairie ecosystems, american bison, greater prairie-chickens, badgers, and armadillo are common, and some of the nation's largest prairie dog towns inhabit shortgrass prairie in the state's panhandle. The Cross Timbers, a region transitioning from prairie to woodlands in Central Oklahoma, harbors 351 vertebrate species. The Ouachita Mountains are home to black bear, red fox, grey fox, and river otter populations, which coexist with a total of 328 vertebrate species in southeastern Oklahoma.
Oklahoma has 41 state parks, two national protected forests or grasslands, km2) of forest is public land, including the western portions of the Ouachita National Forest, the largest and oldest national forest in the southern United States. With 39,000 acres (160 km2), the Tallgrass Prairie Preserve in north-central Oklahoma is the largest protected area of tallgrass prairie in the world and is part of an ecosystem that encompasses only 10 percent of its former land area, once covering 14 states. In addition, the Black Kettle National Grassland covers 31,300 acres (127 km2) of prairie in southwestern Oklahoma. The Wichita Mountains Wildlife Refuge is the oldest and largest of nine national wildlife refuges in the state and was founded in 1901, encompassing 59,020 acres (238.8 km2). Of Oklahoma's federally protected park or recreational sites, the Chickasaw National Recreation Area is the largest, with 4,500 acres (18 km2). Other federal protected sites include the Santa Fe and Trail of Tears national historic trails, the Fort Smith and Washita Battlefield national historic sites, and the Oklahoma City National Memorial.and a network of wildlife preserves and conservation areas. Six percent of the state's 10 million acres (40,000
Oklahoma sits at a frequent crossroads between three different air masses: warm, humid air from the Gulf of Mexico; warm to hot, dry air from Mexico and the Southwestern U.S.; and cold, dry air from Canada. Especially from fall to spring, Oklahoma sees frequent air mass changes, which can produce drastic swings in both temperature and humidity. Much of the state is often subjected to extremes in temperature, wind, drought, and rainfall.Most of the state lies in an area known as Tornado Alley characterized by frequent interaction between cold and warm air masses, producing severe weather, with the highest-risk months from April to June. An average of 62 tornadoes strike the state per year, making that one of the highest rates in the world. Due to its position between zones of differing prevailing temperature and winds, weather patterns within the state can vary widely between relatively short distances. Precipitation occurs year-round, but average monthly precipitation is generally lowest in the winter months, rises dramatically to a peak in May (the year's wettest month virtually statewide, owing to frequent, and not uncommonly severe, thunderstorm activity), and decreases again by mid-summer, when long stretches of hot, dry weather are common in July and August many years. Early to mid fall (September and October) often sees a secondary precipitation maximum. From late October to December, precipitation generally decreases again.
Eastern Oklahoma has a humid subtropical climate (Köppen Cfa) heavily influenced by southerly winds bringing moisture from the Gulf of Mexico and has hot, humid summers and generally mild winters, but with sometimes-dramatic cold spells, sometimes accompanied by snow, sleet or freezing rain. This transitions progressively to a semi-arid zone (Köppen BSk) in the high plains of the Panhandle, where a drier climate prevails, with somewhat-colder winters and similarly-hot summers but much lower humidity. Other central to western areas of the state, including Lawton and Enid in the transition zone, are also less affected by moisture from the Gulf of Mexico. They also tend to be drier than Oklahoma's eastern counties. °F (17 °C) and an annual rainfall of over 40 and as high as 56 inches (1,420 mm), while areas of the panhandle average 58 °F (14 °C), with an annual rainfall under 17 inches (430 mm). All of the state frequently experiences temperatures above 100 °F (38 °C), or below 0 °F (−18 °C) (though subzero temperatures are rare in southeastern Oklahoma), and snowfall ranges from an average of less than 4 inches (10 cm) in the far south to just over 20 inches (51 cm) on the border of Colorado in the panhandle. The state is home to the National Storm Prediction Center of the National Weather Service located in Norman. Winter and spring weather often are influenced by the El Niño Southern Oscillation. Winters during El Niño are cooler than average and wetter across the western portion of the state due to an amplified southern jet stream. During La Niña, the storm track is further north, therefore winters are warmer than average and drier in the western part of the state.Precipitation and temperatures fall from east to west accordingly, with areas in the southeast averaging an annual temperature of 62
The Ouachita National Forest is a National Forest that lies in the western portion of Arkansas and portions of eastern Oklahoma.
The Tallgrass prairie is an ecosystem native to central North America. Natural and anthropogenic fire, as well as grazing by large mammals, were historically agents of periodic disturbance, which regulates tree encroachment, recycles nutrients to the soil, and catalyzes some seed dispersal and germination processes. Prior to widespread use of the steel plow, which enabled conversion to agricultural land use, tallgrass prairies expanded throughout the American Midwest and smaller portions of southern central Canada, from the transitional ecotones out of eastern North American forests, west to a climatic threshold based on precipitation and soils, to the southern reaches of the Flint Hills in Oklahoma, to a transition into forest in Manitoba.
The Midewin National Tallgrass Prairie (MNTP) is a tallgrass prairie reserve and United States National Grassland operated by the United States Forest Service. The first national tallgrass prairie ever designated in the U.S. and the largest conservation site in the Chicago Wilderness region, it is located on the site of the former Joliet Army Ammunition Plant between the towns of Elwood, Manhattan and Wilmington in northeastern Illinois. Since 2015, it has hosted a conservation herd of American bison to study their interaction with prairie restoration and conservation.
The Texas Blackland Prairies are a temperate grassland ecoregion located in Texas that runs roughly 300 miles (480 km) from the Red River in North Texas to San Antonio in the south. The prairie was named after its rich, dark soil.
The Tallgrass Prairie Preserve, located in Osage County, Oklahoma near Foraker, Oklahoma, is owned and managed by The Nature Conservancy. It is protected as the largest tract of remaining tallgrass prairie in the world. The preserve contains 39,000 acres (160 km2) owned by the Conservancy and another 6,000 acres (24 km2) leased in what was the original tallgrass region of the Great Plains that stretched from Texas to Manitoba.
Wichita Mountains Wildlife Refuge, located in southwestern Oklahoma near Lawton, has protected unique wildlife habitats since 1901 and is the oldest managed wildlife facility in the United States Fish and Wildlife Service system. Measuring about 59,020 acres (238.8 km2), the refuge hosts a great diversity of species: 806 plant species, 240 species of birds, 36 fish, and 64 reptiles and amphibians are present. The refuge's location in the geologically unique Wichita Mountains and its areas of undisturbed mixed grass prairie make it an important conservation area. The Wichitas are approximately 500 million years old.
Rita Blanca National Grassland is a National Grassland on the Great Plains near the community of Texline in northwest Dallam County, Texas, in the Texas Panhandle, and in southern Cimarron County, Oklahoma, in the western Oklahoma Panhandle. The principal city in the area is Dalhart, Texas, which houses the XIT Museum.
The geography of Texas is diverse and large. Occupying about 7% of the total water and land area of the U.S., it is the second largest state after Alaska, and is the southernmost part of the Great Plains, which end in the south against the folded Sierra Madre Oriental of Mexico. Texas is in the south-central part of the United States of America, and is considered to form part of the U.S. South and also part of the U.S. Southwest.
The Osage Plains are a physiographic section of the larger Central Lowland province, which in turn is part of the larger Interior Plains physiographic division. The area is sometimes called the Lower Plains, North Central Plains,or Rolling Plains. The Osage Plains, covering west-central Missouri, the southeastern third of Kansas, most of central Oklahoma, and extending into north-central Texas, is the southernmost of three tallgrass prairie physiographic areas. It grades into savanna and woodland to the east and south, and into shorter, mixed-grass prairie to the west. The Osage Plains consist of three subregions. The Osage Plains proper occupy the northeast segment. Although sharply demarcated from the Ozark uplift, the plains are nonetheless a transitional area across which the boundary between prairie and woodland has shifted over time. In the central portion of the physiographic area lies the second subregion, the Flint Hills, commonly called "the Osage" in Oklahoma. This large remnant core of native tallgrass prairie is a rocky rolling terrain that runs from north to south across Kansas and extends into Oklahoma. To the west and south of these hills are the Blackland Prairies and Cross Timbers. This vegetatively complex region of intermixed prairie and scrubby juniper-mesquite woodland extends into north-central Texas. Bluestem prairies and oak-dominated savannas and woodlands characterize the natural vegetation in the Cross Timbers. Much of the area has been converted to agriculture, although expanses of oak forest and woodland are still scattered throughout the eastern portion of the subregion.
The natural history of Minnesota covers many plant and animal species in the U.S. state of Minnesota. The continental climate and location of Minnesota at the physiographic intersection of the Laurentian and the Interior Plains influences its plant and animal life. Three of North America's biomes converge in Minnesota: prairie grasslands in the southwestern and western parts of the state, the eastern temperate deciduous forests in the east-central and the southeast and the coniferous forest in the north-central and northeast.
Glacial Ridge National Wildlife Refuge was created on October 12, 2004, the 545th National Wildlife Refuge in the United States. Its creation was the result of cooperation between at least 30 agencies or governmental entities. The creation of the refuge was spearheaded by The Nature Conservancy, and the initial endowment of 2,300 acres (9.3 km2) of land was donated by the Conservancy. In light of its planned final size of 37,756 acres (153 km2), it is described by the US Fish and Wildlife Service as "the largest tallgrass prairie and wetland restoration project in U.S. history."
The shortgrass prairie is an ecosystem located in the Great Plains of North America. The prairie includes lands to the west as far as the eastern foothills of the Rocky Mountains and extends east as far as Nebraska and north into Saskatchewan. The prairie stretches through parts of Alberta, Wyoming, Montana, North Dakota, South Dakota, and Kansas, and passes south through the high plains of Colorado, Oklahoma, Texas, and New Mexico.
The Little River is a tributary of the Red River, with a total length of 217 miles (349 km), 130 miles (210 km) in southeastern Oklahoma and 87 miles (140 km) in southwestern Arkansas. in southeastern Oklahoma and southwestern Arkansas in the United States. Via the Red, it is part of the watershed of the Mississippi River. Six large reservoirs impound the Little River and its tributaries. The drainage basin of the river totals 4,204 square miles (10,890 km2), 2,204 square miles (5,710 km2) in Oklahoma and 2,036 square miles (5,270 km2) in Arkansas. The Little River and its upper tributaries are popular for recreational canoeing and kayaking.
The geography of Arkansas varies widely. The state is covered by mountains, river valleys, forests, lakes, and bayous in addition to the cities of Arkansas. Hot Springs National Park features bubbling springs of hot water, formerly sought across the country for their healing properties. Crowley's Ridge is a geological anomaly rising above the surrounding lowlands of the Mississippi embayment.
The Kiamichi Mountains are a mountain range in southeastern Oklahoma. A subrange within the larger Ouachita Mountains that extend from Oklahoma to western Arkansas, the Kiamichi Mountains sit within Le Flore, Pushmataha, and McCurtain counties near the towns of Poteau and Albion. The foothills of the Kiamichi Mountains sit within Haskell County, Northern Le Flore County, and Northern Pittsburg County. Its peaks, which line up south of the Kiamichi River, reach 2,500 feet in elevation. The range is the namesake of Kiamichi Country, the official tourism designation for southeastern Oklahoma.
The Western short grasslands is a temperate grassland ecoregion of the United States.
Tallgrass most frequently refers to the native North American grasslands, Tallgrass prairie. Many events, businesses, and locations have been named after the prairie including:
The Central Great Plains are a semi-arid prairie ecoregion of the central United States, part of North American Great Plains. The region runs from west-central Texas through west-central Oklahoma, central Kansas, and south-central Nebraska.
The Arkansas Valley is a Level III ecoregion designated by the Environmental Protection Agency (EPA) in the U.S. states of Arkansas and Oklahoma. It parallels the Arkansas River between the flat plains of western Oklahoma and the Arkansas Delta, dividing the Ozarks and the Ouachita Mountains with the broad valleys created by the river's floodplain, occasionally interrupted by low hills, scattered ridges, and mountains. In Arkansas, the region is often known as the Arkansas River Valley, especially when describing the history and culture of the region.