The Snake River is a major river in the interior Pacific Northwest region of the United States. About 1,080 miles (1,740 km) long, it is the largest tributary of the Columbia River, which is the largest North American river that empties into the Pacific Ocean. Beginning in Yellowstone National Park, western Wyoming, it flows across the arid Snake River Plain of southern Idaho, the rugged Hells Canyon on the borders of Idaho, Oregon and Washington, and finally the rolling Palouse Hills of southeast Washington. It joins the Columbia River just downstream from the Tri-Cities, Washington, in the southern Columbia Basin.
Interstate 82 (I-82) is an Interstate Highway in the Pacific Northwest region of the United States that travels through parts of Washington and Oregon. It runs 144 miles (232 km) from its northwestern terminus at I-90 in Ellensburg, Washington, to its southeastern terminus at I-84 in Hermiston, Oregon. The highway passes through Yakima and the Tri-Cities, and is also part of the link between Seattle and Salt Lake City, Utah. I-82 travels concurrently with U.S. Route 97 (US 97) between Ellensburg and Union Gap; US 12 from Yakima to the Tri-Cities; and US 395 from Kennewick to Umatilla, Oregon.
Hermiston is a city in Umatilla County, Oregon, United States. Its population of 20,322 makes it the largest city in Eastern Oregon. Hermiston is the largest and fastest-growing city in the Hermiston-Pendleton Micropolitan Statistical Area, the eighth largest Core Based Statistical Area in Oregon with a combined population of 92,261 at the 2020 census. Hermiston sits near the junction of I-82 and I-84, and is 7 miles south of the Columbia River, Lake Wallula, and the McNary Dam. The Hermiston area has become a hub for logistics and data center activity due to the proximity of the I-82 and I-84 interchange, Pacific Northwest fiber optic backbone, and low power costs.
Umatilla is a city in Umatilla County, Oregon, United States. The population in 2010 was 6,906, but the city's population includes approximately 2,000 inmates incarcerated at Two Rivers Correctional Institution.
The Walla Walla River is a tributary of the Columbia River, joining the Columbia just above Wallula Gap in southeastern Washington in the United States. The river flows through Umatilla County, Oregon, and Walla Walla County, Washington. Its drainage basin is 1,758 square miles (4,550 km2) in area.
The Grande Ronde River is a 210-mile (340 km) long tributary of the Snake River, flowing through northeast Oregon and southeast Washington in the United States. Its watershed is situated in the eastern Columbia Plateau, bounded by the Blue Mountains and Wallowa Mountains to the west of Hells Canyon. The river flows generally northeast from its forested headwaters west of La Grande, Oregon, through the agricultural Grande Ronde Valley in its middle course, and through rugged canyons cut from ancient basalt lava flows in its lower course. While it joins the Snake River upstream of Asotin, Washington, more than 90 percent of the river's watershed is in Oregon.
McNary Dam is a 1.4-mile (2.2-km) long concrete gravity run-of-the-river dam which spans the Columbia River. It joins Umatilla County, Oregon with Benton County, Washington, 292 miles (470 km) upriver from the mouth of the Columbia. It is operated by the U.S. Army Corps of Engineers' McNary Lock and Dam office. The dam is located a mile (2 km) east of the town of Umatilla, Oregon, and 8 miles (13 km) north of Hermiston, Oregon. The dam was originally planned to be named Umatilla Dam, but the Flood Control Act of 1945 renamed the dam in honor of Senator Charles L. McNary of Oregon, who had died the previous year.
The Lewis and Clark National Historical Park, located in the vicinity of the mouth of the Columbia River, commemorates the Lewis and Clark Expedition. Administration of the park, which includes both federal and state lands, is a cooperative effort of the National Park Service and the states of Oregon and Washington. The National Historical Park was dedicated on November 12, 2004.
Beacon Rock State Park is a geologic preserve and public recreation area on Route 14 in the Columbia River Gorge National Scenic Area in Skamania County, Washington, United States. The park takes its name from Beacon Rock, an 848-foot (258 m) basalt volcanic plug on the north shore of the Columbia River 32 miles (51 km) east of Vancouver. On October 31, 1805, the Lewis and Clark Expedition arrived here and first measured tides on the river, indicating that they were nearing the ocean.
U.S. Route 730 (US 730) is an east–west United States Numbered Highway, of which all but 6.08 miles of its 41.78 miles are within the state of Oregon. The highway starts in rural Morrow County in Eastern Oregon at an interchange with Interstate 84 (I-84) and US 30, located east of the city of Boardman. US 730 travels east along the Columbia River as a continuation of Columbia River Highway No. 2 into Umatilla County, intersecting I-82 and US 395 in the city of Umatilla. US 730 and US 395 form a short concurrency within the city before the highways part, and US 730 continues northeast into Washington. The highway travels through rural Walla Walla County and ends at an intersection with US 12 south of Wallula.
Wallula Gap is a large water gap of the Columbia River in the northwest United States in southeast Washington. It cuts through the Horse Heaven Hills basalt anticlines in the Columbia River Basin, just south of the confluence of the Walla Walla and Columbia rivers.
The Umatilla River is an 89-mile (143 km) tributary of the Columbia River in northern Umatilla County, Oregon, United States. Draining a basin of 2,450 square miles (6,300 km2), it enters the Columbia near the city of Umatilla in the northeastern part of the state. In downstream order, beginning at the headwaters, major tributaries of the Umatilla River are the North Fork Umatilla River and the South Fork Umatilla River, then Meacham, McKay, Birch, and Butter creeks.
The Umatilla National Forest, in the Blue Mountains of northeast Oregon and southeast Washington, covers an area of 1.4 million acres (5,700 km2). In descending order of land area the forest is located in parts of Umatilla, Grant, Columbia, Morrow, Wallowa, Union, Garfield, Asotin, Wheeler, and Walla Walla counties. More than three-quarters of the forest lies in the state of Oregon. Forest headquarters are located in Pendleton, Oregon. There are local ranger district offices in Heppner and Ukiah in Oregon, and in Pomeroy and Walla Walla in Washington.
The Horse Heaven Hills are a long range of high, rolling hills in Klickitat, Yakima, and Benton counties in Washington. The hills are an anticline ridge in the Yakima Fold Belt formed by north–south compression of lava flows in the Columbia River Basalt Group. The highest point is Bickleton Ridge in the west end of the hills. They lie within the rain shadow to the east of the Cascade Range, making them significantly drier and hotter than regions west of the Cascades.
Lake Wallula is a reservoir on the Columbia River in the United States, between the U.S. states of Washington and Oregon. It was created in 1954 with the construction of McNary Dam. It reaches from McNary Dam near the city of Umatilla, Oregon, to the Tri-Cities of Washington.
The Ice Age Floods National Geologic Trail is a network of routes connecting natural sites and facilities that provide interpretation of the geological consequences of the Glacial Lake Missoula floods of the last glacial period that occurred about 18,000 to 15,000 years ago. It includes sites in Washington, Oregon, Idaho, and Montana. It was designated as the first National Geologic Trail in the United States in 2009.
The McNary Levee System, also known as the Tri-Cities Levees, is an appurtenant or dam-related structure to McNary Lock and Dam, and consists of three groups of levee segments along the banks of the Columbia River that provide flood risk reduction for portions of Kennewick, Pasco, and Richland, Washington. The levee group names are based on location and are identified as the Kennewick Levees, Pasco Levees, and Richland Levees. Lake Wallula behind McNary Lock and Dam is about 63 miles long and includes 242 miles of shoreline and a drainage area of 214,000 square miles. The McNary Levee System consists of about 16.8 miles of earthen levees and 11 operational pump plants that remove agricultural runoff, groundwater migration, and rainfall runoff. Construction of the McNary Levee System began in 1950 and was completed in 1954.
The Yakima River Delta is an area of land in Richland, Washington where the Yakima River enters the Columbia River at River Mile 335. It hosts several protected areas and is crossed by State Route 240. This area is mostly floodplain with riparian-type growth, including non-native species such as Russian olive. Amon Creek enters the Yakima River in this area.
The 2020 Pacific Northwest floods were a series of floods in the Pacific Northwest, United States. The main impacts were experienced in the northwest quarter of Washington and along rivers and streams draining the Blue Mountains in southeast Washington and northeast Oregon. Small portions of the Lower Mainland in British Columbia, Canada also flooded. The flooding was primarily caused by heavy rain falling on mountain snow and represents the worst flood on record for some of the affected rivers. Large rivers in the region, such as the Columbia and Snake were largely unaffected.
The following is a timeline of the history of Oregon in the United States of America.
