|Santa Ana Mountains|
|Elevation||5,689 ft (1,734 m)|
|Coordinates||33°42′38″N117°32′03″W / 33.71056°N 117.53417°W Coordinates: 33°42′38″N117°32′03″W / 33.71056°N 117.53417°W|
|Length||61 mi (98 km)|
|Area||2,104 sq mi (5,450 km2)|
|Counties||Orange, Riverside and San Diego|
|Age of rock||Triassic and Jurassic  |
|Type of rock||Metasedimentary |
The Santa Ana Mountains are a short peninsular mountain range along the coast of Southern California in the United States. They extend for approximately 61 miles (98 km) southeast of the Los Angeles Basin largely along the border between Orange and Riverside counties.
The range starts in the north at the Whittier Fault and Santa Ana Canyon, through which the Santa Ana River flows. To the north of the canyon are the smaller Chino Hills in Los Angeles and San Bernardino counties.  The northernmost summit of the Santa Anas, at 3,045 feet (928 m), is Sierra Peak. From there, the major summits are Pleasants Peak, 4,007 feet (1,221 m); Bedford Peak, 3,800 feet (1,200 m); and Bald Peak, 3,947 feet (1,203 m). The next two peaks, Modjeska, 5,496 feet (1,675 m); and Santiago, 5,689 feet (1,734 m),  the highest summit in the range; form Saddleback Ridge. Saddleback, located approximately 20 mi (32 km) east of Santa Ana, is visible from much of Southern California.
South of Saddleback are Trabuco Peak, 4,613 feet (1,406 m); Los Pinos Peak, 4,510 feet (1,370 m) and Sitton Peak, 3,273 feet (998 m). Elsinore Peak, 3,575 feet (1,090 m) is included in a subrange called the Elsinore Mountains, which are west of Lake Elsinore. San Mateo Peak 3,591 feet (1,095 m) marks the highpoint of this range. Margarita Peak, 3,189 feet (972 m); and Redonda Mesa, 2,825 feet (861 m) are part of the Santa Margarita Mountains, a subrange of the Santa Anas that extends down to Camp Pendleton and Fallbrook. Southeast of the Elsinore Mountains is the Santa Rosa Plateau, named for the Rancho Santa Rosa that once encompassed it. At the south end of the plateau there is a steep escarpment from the basalt capped mesas that line it, that descends from about 500 feet at Mesa de Burro to Sandia Creek on the east to about 1800 feet at Avenaloca Mesa to De Luz Creek in the west. From the foot of the escarpment, the mountains and canyons of De Luz, Sandia Creek and others below it, run to the south to the Santa Margarita River. The range ends roughly at the Santa Margarita River.
Much of the range is within the Trabuco Ranger District of the Cleveland National Forest, although some parts are still owned by two century-old ranches: the Irvine Ranch (originally known as the Yorba Family's Rancho Lomas de Santiago) and Rancho Mission Viejo (originally recorded as Rancho Misión Vieja).
The Santa Anas include a number of high-mountain streams that flow for all or most of the year, although once out of the foothills these waterways are ephemeral. The major streams rising from the western side of the range drain into the Pacific Ocean; these include Peters Canyon Wash, Serrano Creek, San Diego Creek, Aliso Creek, Trabuco Creek, San Juan Creek, and San Mateo Creek. The northern side of the range is defined by the Santa Ana River, which heads about 50 miles (80 km) further east, in the San Bernardino Mountains. Santiago Creek drains much of the northern part of the range and empties into the Santa Ana River near downtown Orange.
Water from the north-east side of the range empties into Temescal Creek which flows north to the Santa Ana River,  or Lake Elsinore which intermittently overflows to Temescal Creek. The southeast end of the range is marked by the Santa Margarita River, which also originates east of the Santa Anas and flows southwest to the Pacific. Runoff from the southeast side of the range drains into Murrieta Creek, a tributary of the Santa Margarita River.
Irvine Lake, the largest body of fresh water in Orange County, is in the northwest part of the range near Villa Park. The lake is formed by the Santiago Dam, which impounds Santiago Creek.
The climate is Mediterranean, with warm dry summers and cool wet winters. Annual precipitation totals range from 20 to 30 inches (500–760 mm) in the higher parts of the range above 3,000 feet (910m), as compared to the average of 13–16 inches (350–400 mm) in the coastal plain. Most of the precipitation falls between November and March. The western (coastal) slope is generally moister than the eastern slope. Snow falls during winter on the highest peaks.
The mountains were named by members of Gaspar de Portolà's expedition, who camped below the mountains on July 26, 1769, the Feast Day of Saint Anne.  At the time of Portola's visit, the Santa Anas were settled by three main groups of indigenous peoples, the Tongva in the north, the Acjachemen in the west and Payomkowishum in the east and south. 
A handful of historic sites remain in the range today. Registered California Historical Landmarks include an Indian Village Site in Black Star Canyon, Flores Peak named for the outlaw Juan Flores, the mining boomtown sites of Carbondale and Silverado, and Helena Modjeska's home.  The Moreno and Machado Adobes of the Rancho Santa Rosa are found on the Santa Rosa Plateau Ecological Reserve.  Beeks Place, a small house foundation still owned by the family, is also located here.
The mountains were the site of the Indian massacre of Puhú village in 1831 in Black Star Canyon. 
As part of the California Floristic Province, the Santa Ana Mountains host a diverse array of plant species within distinctive natural (plant) communities, including coastal sage scrub, chaparral, riparian woodland, southern oak woodland, rocky outcrop, vernal pool, valley grassland, and closed-cone montane coniferous forest. One of the southernmost stands of madrones can be found in Trabuco Canyon. Groves of knobcone pine can be found around Pleasants Peak. Big-cone Douglas fir and Coulter pine can be found at the higher elevations. Rare flowers like the intermediate Mariposa lily, heart-leaved pitcher sage (associated with the Tecate cypress), and chocolate lily are difficult to find. Fragrant sages, broadleaf evergreen shrubs and trees, perennial bunchgrasses, succulents ( Dudleya species), and fire-following flowers grow in the rugged terrain. Numerous ferns, including large sword ferns, are found under trees and near streams, especially at higher elevations.
A surprising variety of wildlife species can be found, including mountain lion,  mule deer, bobcat, coyote, gray fox, American badger, ring-tailed cat, spotted skunk, western gray squirrel, long-tailed weasel, dusky-footed woodrat, kangaroo rat, bats, spotted owl, western pond turtle, steelhead, coast horned lizard, least Bell's vireo, golden eagle, mountain quail, canyon wren, speckled rattlesnake, Pacific rattlesnake, common kingsnake, gopher snake, western fence lizard, arroyo toad, western spadefoot toad, California tree frog, California sister butterfly, various Aphonopelma species of tarantula, and many more.
The last wild California grizzly bear in the Santa Ana Mountains was shot and killed in the mountains in 1908.  Gray wolf, pronghorn, California condor and possibly jaguar were also once found in the range.
A number of minerals have been mined in the range, though none were very profitable. Commercial resources collected since the 1870s have included metals such as lead, silver, tin, and zinc, and minerals such as clay, coal, gypsum, and limestone.  Parts of the range have been used to graze domestic livestock and harvest timber since the late 18th century. As the surrounding cities have grown, the water of the range's creeks has become a particularly valued resource. 
The mountains form a natural barrier between the Inland Empire region to the east and the job centers of Orange County to the west. Only one freeway, the Riverside Freeway (State Route 91), the tolled Foothill and Eastern Transportation Corridor (State Route 241), and the two-lane Ortega Highway (State Route 74) connect the regions. Highway 91, which follows the Santa Ana River through a pass between the Santa Ana Mountains on the south and the Chino Hills on the north, is one of California's most congested routes. Because of this, several proposals have been floated to excavate a highway tunnel through the Santa Ana Mountains, although the multibillion-dollar idea has drawn criticism from environmentalists and others concerned about cost and safety in the earthquake-prone region. While Highway 91 is one of the most congested routes in California, Highway 74 holds a more ominous claim as one of the most dangerous highways in the state. State route 241 starts in Mission Viejo and travels along side the Foothills of the Santa Ana's while merging with State Route 133 and 261. The highway finishes at the junction with State Route 91. 
Rancho Santa Margarita is a city in Orange County, California, United States. One of Orange County's youngest cities, Rancho Santa Margarita is a master-planned community. The population was 47,853 at the 2010 census, up from 47,214 at the 2000 census. Although it is named for Rancho Santa Margarita y Las Flores, which was in San Diego County, the city limits fall within the borders of Rancho Mission Viejo. At 20 characters long, it is the longest city name in California.
The Santa Ana River is the largest river entirely within Southern California in the United States. It rises in the San Bernardino Mountains and flows for most of its length through San Bernardino and Riverside Counties, before cutting through the northern Santa Ana Mountains via Santa Ana Canyon and flowing southwest through urban Orange County to drain into the Pacific Ocean. The Santa Ana River is 96 miles (154 km) long, and its drainage basin is 2,650 square miles (6,900 km2) in size.
Trabuco Canyon is a small unincorporated community located in the foothills of the Santa Ana Mountains in eastern Orange County, California, and lies partly within the Cleveland National Forest.
Cleveland National Forest encompasses 460,000 acres, mostly of chaparral, with a few riparian areas. A warm dry mediterranean climate prevails over the forest. It is the southernmost U.S. National Forest of California. It is administered by the U.S. Forest Service, a government agency within the United States Department of Agriculture. It is divided into the Descanso, Palomar and Trabuco Ranger Districts and is located in the counties of San Diego, Riverside, and Orange.
Saddleback Valley refers to the flat and foothill areas west-southwest of the Saddleback double peak of the Santa Ana Mountains and east-northeast of the hilly Crystal Cove State Park in southern Orange County, California. The region primarily encompasses the cities of Mission Viejo, Lake Forest, and Rancho Santa Margarita, as well as the communities of Coto de Caza and Ladera Ranch. The cities of Aliso Viejo, Laguna Woods, Laguna Hills, and Laguna Niguel, as well as some of Orange County's eastern canyon communities, partially reside within the valley. The southeastern portion of Irvine also encroaches upon the area, but the two are not typically associated with each other.
Area code 949 is an area code in the U.S. state of California that is contained within South Orange County California. On April 18, 1998, the southern cities of Orange County were split from 714, creating area code 949. It includes cities such as Newport Beach, Irvine, Lake Forest, Portola Hills, Coto de Caza, Dove Canyon, Aliso Viejo, Trabuco Canyon, Capistrano Beach, Corona del Mar, Laguna Niguel, Laguna Hills, Laguna Woods, Newport Coast, Foothill Ranch, Robinson Ranch, Mission Viejo, San Juan Capistrano, Rancho Santa Margarita, Ladera Ranch, Dana Point, Laguna Beach, and San Clemente. The city of Costa Mesa is shared between the 949 and 714 area codes, being split at Wilson Street and along Newport Boulevard. A very small portion of Irvine is also in the 714 area code, from the north side of Culver Drive at the I-5 to Jamboree Road in the Marketplace, in the neighborhood of Northpark Irvine.
San Juan Creek, also called the San Juan River, is a 29-mile (47 km) long stream in Orange and Riverside Counties, draining a watershed of 133.9 square miles (347 km2). Its mainstem begins in the southern Santa Ana Mountains in the Cleveland National Forest. It winds west and south through San Juan Canyon, and is joined by Arroyo Trabuco as it passes through San Juan Capistrano. It flows into the Pacific Ocean at Doheny State Beach. San Juan Canyon provides a major part of the route for California State Route 74.
Rancho Santiago de Santa Ana was a 63,414-acre (256.63 km2) Spanish land concession in present-day Orange County, California, given by Spanish Alta California Governor José Joaquín de Arrillaga in 1810 to Jose Antonio Yorba and his nephew Pablo Peralta. The grant extended eastward from the Santa Ana River to the Santa Ana Mountains, with a length of more than 22 miles (35 km).
Santiago Canyon is a canyon and unincorporated community in South Orange County, California. According to the 2000 census, Santiago Canyon has several hundred residents living within its borders. Trabuco Canyon, Silverado Canyon, Modjeska Canyon and Williams Canyon are tributaries of Santiago Canyon. Santiago Creek flows northwest from the canyon, then west into the Santa Ana River. Neighborhoods in Santiago Canyon include Santiago Canyon Estates and Falcon View Estates. The landmark Cook's Corner motorcycle restaurant is also located within Santiago Canyon.
Arroyo Trabuco is a 22-mile (35 km)-long stream in coastal southern California in the United States. Rising in a rugged canyon in the Santa Ana Mountains of Orange County, the creek flows west and southwest before emptying into San Juan Creek in the city of San Juan Capistrano. Arroyo Trabuco's watershed drains 54 square miles (140 km2) of hilly, semi-arid land and lies mostly in Orange County, with a small portion extending northward into Riverside County. The lower section of the creek flows through three incorporated cities and is moderately polluted by urban and agricultural runoff.
Santiago Creek is a major watercourse in Orange County in the U.S. state of California. About 34 miles (55 km) long, it drains most of the northern Santa Ana Mountains and is a tributary to the Santa Ana River. It is one of the longest watercourses entirely within the county. The creek shares its name with Santiago Peak, at 5,687 ft (1,733 m) the highest point in Orange County, on whose slopes its headwaters rise.
San Diego Creek is a 16-mile (26 km) urban waterway flowing into Upper Newport Bay in Orange County, California in the United States. Its watershed covers 112.2 square miles (291 km2) in parts of eight cities, including Irvine, Tustin, and Costa Mesa. From its headwaters in Laguna Woods the creek flows northwest to its confluence with Peters Canyon Wash, where it turns abruptly southwest towards the bay. Most of the creek has been converted to a concrete flood control channel, but it also provides important aquatic and riparian habitat along its course and its tidal estuary.
Bell Canyon is a major drainage of the Santa Ana Mountains in Orange County, California in the United States. Bell Creek flows about 14.4 miles (23.2 km) in a southerly direction to its confluence with San Juan Creek. The Bell Canyon drainage is located to the east and parallel to Cañada Gobernadora, and to the south of Trabuco Creek. After Trabuco Creek, it is the second largest tributary of San Juan Creek in terms of length and its watershed area of 26 square miles (67 km2).
San Mateo Creek is a stream in Southern California in the United States, whose watershed mostly straddles the border of Orange and San Diego Counties. It is about 22 miles (35 km) long, flowing in a generally southwesterly direction. Draining a broad valley bounded by the Santa Ana Mountains and Santa Margarita Mountains, San Mateo Creek is notable for being one of the last unchannelized streams in Southern California.
The Elsinore Mountains are a ridge of mountains within the larger range of the Santa Ana Mountains, in the Cleveland National Forest, Riverside County, California, United States. the tallest peaks within the range is the unofficially named San Mateo Peak at 3,591 ft (1,095 m). Second is officially named Elsinore Peak at 3,536 ft (1,078 m). The Elsinore Mountanins run in a ridge from just east of El Cariso, southeast to Elsinore Peak. Beyond that peak the ridge begins to descend and curves to the east. From Elsinore Peak, a ridge runs to the west and then northwest to San Mateo Peak, enclosing the Morrell Potrero on the south and west.
Trabuco Peak is a 4,607-foot (1,404 m) summit in the Santa Ana Mountains on the border of Orange and Riverside Counties, California, about halfway between Rancho Santa Margarita and Lake Elsinore. The mountain sits on the divide between Arroyo Trabuco on the west and the Temescal Creek valley on the east. Situated in the Cleveland National Forest, it is the highest summit in the Santa Anas south of Santiago Peak.
Los Pinos Peak is a 4,455-foot (1,358 m) summit in the Santa Ana Mountains in Orange County, California, about 8 miles (13 km) east of Rancho Santa Margarita. Los Pinos is the southernmost peak above 4,000 feet (1,200 m) in the Santa Anas, and provides extensive views south towards San Diego and the Pacific Ocean as well as views of the San Jacinto Mountains and San Bernardino Mountains in the east. The summit rises rather prominently above the main crest of the Santa Anas and is conspicuously visible from much of southern Orange County, although its actual topographic prominence is only about 610 feet (186 m).
The Holy Fire was a wildfire that burned in the Cleveland National Forest in Orange and Riverside Counties, California. The wildfire started on August 6, 2018 at around 1:15 PM PDT, in the vicinity of Trabuco Canyon. The suspected arsonist, Forrest Gordon Clark, was booked into the Orange County jail in Santa Ana, California. The blaze burned 23,136 acres (94 km2) and destroyed 18 buildings, before it was fully contained on September 13, 2018. While the fire was actively spreading in early and mid-August, residents of the nearby cities of Corona, Temescal Valley, and Lake Elsinore were placed under evacuation orders.