San Gabriel Wilderness

Cogswell Dam is a rockfill dam on the West Fork of the San Gabriel River in Los Angeles County, California. It is located in the San Gabriel Mountains, northeast of Mount Wilson, and within the Angeles National Forest. It forms Cogswell Reservoir, which has a capacity of 8,969 acre-feet (11,063,000 m3).The dam serves mainly for flood control in conjunction with San Gabriel Dam and Morris Dam downstream. San Gabriel Dam lies 13 miles (21 km) downstream.

Monrovia Peak is a 5,412-foot-elevation (1,650 meter) mountain summit located in the San Gabriel Mountains, in Los Angeles County, California, United States.

Stony Ridge Observatory is an astronomical observatory built by and for amateur astronomers in the mountains of Los Angeles County, California, in 1957. When installed, its 760 mm (30 in) Newtonian-Cassegrain likely ranked as 8th largest of all telescopes in California, and one of the largest amateur telescopes in the United States. The telescope is designed so that one of four Newtonian foci, or a Cassegrain focus, can be used. Asteroids 10168 Stony Ridge, 144633 Georgecarroll and 327030 Alanmaclure, were discovered at the observatory, and other scientific research (including an extensive lunar photography and mapping project in cooperation with Lockheed upon which the decision on the lunar lander touchdown site was based) has been conducted there. The observatory also has a 12-inch Cassegrain telescope and a number of accessory items, including CCD cameras and computer equipment. Facilities include an administration building with a small galley and bunkroom, the dome containing the 30-inch telescope, and a vault-style outhouse. The facility has Edison electric power and a landline telephone connection, but water must be carried in. Stony Ridge is located on a remote, restricted-access site north of Mt. Wilson, near Charlton Flat in the Angeles National Forest. In September 2009, Stony Ridge was at risk of being lost to a wildfire but escaped with minimal fire damage to one side of the outhouse building, although nearby ground cover was burned away, and the foliage of surrounding Coulter pines was destroyed.Recent restoration projects, completed in mid-2017, included: Re-installation of the original, George Carroll-designed right ascension and declination drive systems; installation of a Software Bisque-based "go to" system which will point the telescope at a computer-selected celestial object too faint to be seen with the naked eye or the telelescope's finder scopes; stripping and re-aluminization of the primary and secondary mirrors, which were significantly deteriorated by age, as well as smoke and heat from the infamous Station Fire, which burned more than 200 square miles of the Angeles National Forest surrounding the observatory in 2009.

The Gabrielino Trail is a United States National Recreation Trail that runs through the Angeles National Forest. Its western trailhead is at Windsor Avenue in Altadena, California, and it runs generally east/west, with its eastern end at Chantry Flat, just north of Arcadia, California. It passes through three major watersheds and has an elevation gain/loss of 3,500 ft (1,100 m).

Chantry Flat is a designated "Recreation Area" within the Angeles National Forest, about three miles (5 km) into Big Santa Anita Canyon, and is closely associated with the towns of Arcadia and Sierra Madre, CA. The flat itself houses a large public picnic area, and is the starting point for several historic trails of the San Gabriel Mountains, including the 28.5-mile (45.9 km) Gabrielino Trail. The US Forest Service estimates the road to Chantry as the third busiest entry into the Angeles, next to CA State Highways 2 and 39.

The Silver Moccasin Trail is a 53-mile (85 km) trail located in the San Gabriel Mountains, northeast of Los Angeles. It begins at Chantry Flat Recreation Area above the city of Arcadia, California, traversing upward and down through several canyons and along the high ridges of the Angeles National Forest. This trail connects Mt. Baden-Powell, Mount Burnham, Throop Peak and Mount Hawkins. It comes to its highest point of 9,399 feet (2,865 m) at Mount Baden-Powell after which point it descends to its terminus at Vincent Gap on the Angeles Crest Highway near Wrightwood.

Vetter Mountain is located in the San Gabriel Mountains and within the Angeles National Forest, Los Angeles County, California, United States. Elevation 5,911 feet (1,802 m) feet. Named by USFS surveyor Don McLain (c. 1933) for Victor P. Vetter (nd.), a dedicated forest ranger and fire dispatcher. Vetter won the USFS Bissell Medal for outstanding work in forest conservation (1930). The Silver Moccasin Trail crosses the mountain on its eastern slopes.

Santa Anita Dam, also known as Big Santa Anita Dam, is a concrete thin arch dam on Santa Anita Creek in the San Gabriel Mountains of Los Angeles County, California. Owned by the Los Angeles County Flood Control District, the dam serves for flood control, water conservation and debris control. The dam is 225 feet (69 m) high and 612 feet (187 m) long, holding 858 acre-feet (1,058,000 m3) of water with a maximum capacity of 1,028 acre⋅ft (1,268,000 m3). The catchment area for the dam is 10.8 square miles (28 km2). The dam was built between 1923 and 1927. The dam has three valves that control releases of stormwater.The dam is situated in the steep San Gabriel foothills, north of Sierra Madre and Arcadia. It is located just north of the boundary of the Angeles National Forest. The dam is visible from Santa Anita Canyon Road, which runs along the west slope of the Santa Anita Canyon and provides access into trails further upstream along Santa Anita Creek. The viewing window for the dam is very short, only about a half-mile; the access road which runs down into the canyon from Santa Anita Canyon Road is closed to the public. However, the First Water trail, which leads downstream from Chantry Flat along the creek, is said to provide access to the reservoir. Since the 1990s the maximum allowed storage of water has been restricted, to ensure that the dam will not collapse due to seismic instability. This has partially caused rapid silting of the reservoir and sediment removal was started in mid-2009. The reservoir was drained and about 6,750,000 cubic yards (5,160,000 m3) of sediment were removed. A staged rescue at the dam was broadcast in November 1958 as an episode of the syndicated U.S. television series Rescue 8 titled "The Chasm".

Hughes Airwest Flight 706 was a regularly scheduled flight operated by American domestic airline Hughes Airwest from Los Angeles, California to Seattle, Washington, with several intermediate stops. On Sunday, June 6, 1971, the McDonnell Douglas DC-9 serving as Flight 706 departed Los Angeles just after 6 p.m. en route to Seattle as a McDonnell Douglas F-4 Phantom II of the United States Marine Corps was approaching Marine Corps Air Station El Toro near Irvine at the end of a flight from Naval Air Station Fallon in Nevada. The two aircraft collided in midair over the San Gabriel Mountains near Duarte, killing all 49 aboard the DC-9 and the F-4 pilot; the F-4 radar intercept officer ejected and survived. The crash of Flight 706 prompted the United States Armed Forces to agree to reduce the number of military aircraft operating under visual flight rules in civilian air corridors and to require military aircraft to contact civilian air traffic controllers.

The Mount Wilson Observatory (MWO) is an astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson, a 5,710-foot (1,740-meter) peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles. The observatory contains two historically important telescopes: the 100-inch (2.5 m) Hooker telescope, which was the largest aperture telescope in the world from its completion in 1917 to 1949, and the 60-inch telescope which was the largest operational telescope in the world when it was completed in 1908. It also contains the Snow solar telescope completed in 1905, the 60 foot (18 m) solar tower completed in 1908, the 150 foot (46 m) solar tower completed in 1912, and the CHARA array, built by Georgia State University, which became fully operational in 2004 and was the largest optical interferometer in the world at its completion. Due to the inversion layer that traps warm air and smog over Los Angeles, Mount Wilson has steadier air than any other location in North America, making it ideal for astronomy and in particular for interferometry. The increasing light pollution due to the growth of greater Los Angeles has limited the ability of the observatory to engage in deep space astronomy, but it remains a productive center, with the CHARA array continuing important stellar research. The initial efforts to mount a telescope to Mount Wilson occurred in the 1880s by one of the founders of University of Southern California, Edward Falles Spence, but he died without finishing the funding effort. The observatory was conceived and founded by George Ellery Hale, who had previously built the 1 meter telescope at the Yerkes Observatory, then the world's largest telescope. The Mount Wilson Solar Observatory was first funded by the Carnegie Institution of Washington in 1904, leasing the land from the owners of the Mount Wilson Hotel in 1904. Among the conditions of the lease was that it allow public access.

The CHARA (Center for High Angular Resolution Astronomy) array is an optical interferometer, located on Mount Wilson, California. The array consists of six 1-metre (40 in) telescopes operating as an astronomical interferometer. Construction was completed in 2003. CHARA is owned by Georgia State University (GSU).

Mount Wilson is a peak in the San Gabriel Mountains, located within the San Gabriel Mountains National Monument and Angeles National Forest in Los Angeles County, California. With only minor topographical prominence the peak is not naturally noticeable from a distance, although it is easily identifiable due to the large number of antennas near its summit. It is a subsidiary peak of nearby San Gabriel Peak. It is the location of the Mount Wilson Observatory, which is an important astronomical facility in Southern California with historic 60-inch (1,524 mm) and 100-inch (2,540 mm) aperture telescopes, and 60-foot (18.3 m) and 150-foot (45.7 m) tall solar towers. The newer CHARA Array, run by Georgia State University, is also sited there and does important interferometric stellar research. The summit is at 5,710 feet (1,740 m). While not the tallest peak in its vicinity, it is high enough in elevation that snow can sometimes interrupt astronomical activities on the mountain. All of the mountains south of the summit are far shorter leading to unobstructed views across the Los Angeles Basin, Orange County, the Inland Empire, and out to Ventura County, San Diego County and the Pacific Ocean. On most days, Santa Catalina Island, some 65 mi (105 km) south, is visible. On clear days, other Channel Islands visible include San Clemente Island at 95 mi (153 km), Santa Barbara Island at 76 mi (122 km), San Nicolas Island at 107 mi (172 km), Santa Cruz Island at 98 mi (158 km) and San Miguel Island at 133 mi (214 km). At an elevation of 5,710 ft (1,740 m), the horizon on the ocean extends 92 mi (148 km). Mount Wilson is also heavily utilized for relay broadcasting of radio and television for the Greater Los Angeles Area.