San Clemente Island
San Clemente Island (SCI) is the southernmost of the Channel Islands of California. It is owned and operated by the United States Navy, and is a part of Los Angeles County. Defined by the United States Census Bureau as Block Group 2 of Census Tract 5991 of Los Angeles County, California, it is 21 nautical miles (39 km) long and contains 147.13 km2 (56.81 sq mi) of land. The island is officially uninhabited as of 2000 U.S. Census. It is estimated, however, that the number of military and civilian personnel present on the island at any given time is at least 300.  The city of San Clemente in Orange County, California is named after the island.
Archeologists have found traces of human occupation on San Clemente Island dating back 10,000 years.
Later inhabitants left trade materials from the northern islands and from the mainland, including Coso obsidian from the California desert. It has not been established what tribe the recent inhabitants belonged to, although the Tongva, who are well attested from Santa Catalina Island, are the most likely candidates. The Chumash, who occupied the northern Channel Islands, may have influenced the inhabitants. Evidence of battles; 'the skeletons of dozens of men piled, one upon another' were also noted on San Clemente and San Nicolas.
The first European to sight the island was Juan Rodríguez Cabrillo in 1542, who named it Victoria. It was renamed by Spanish explorer Sebastián Vizcaíno, who spotted it on November 23, 1602, Saint Clement's feast day. It was used by ranchers, fishermen, and smugglers during the 19th century and into the 20th century.
In 1835, the whaleship Elbe of Poughkeepsie, New York, under Captain Josiah B. Whippey (or Whipple), hunted sperm whales as far north as "St. Clements Island" (San Clemente Island). The American steamship Lansing, as well as the steam-schooner California, both anchored in Pyramid Cove, on the south side of San Clemente Island, to process blue, fin and humpback whales caught by their "killer boats" (steam-driven whale catchers)—the former between 1926 and 1930, and the latter between 1933 and 1937. In 1935, the Norwegian factory ship Esperanza caught blue whales as far north as San Clemente Island.
The US Navy acquired the island in 1934. It is the Navy's only remaining ship-to-shore live firing range, and is the center of the integrated air/land/sea San Clemente Island Range Complex covering 2,620 nm² (8,990 km2).
During World War II, the island was used as a training ground for amphibious landing craft. These small to mid-sized ships were crucial to the island hopping that would be required to attack the islands occupied by the Japanese.
There is a US Navy rocket-test facility on San Clemente. Some Polaris-program test rockets were launched from San Clemente between 1957 and 1960. The SEALAB III project took place off San Clemente in February 1969.
The US Navy uses the island as an auxiliary naval airfield, Naval Auxiliary Landing Field San Clemente Island. The main runway 23/05 is used for carrier training by the Navy. Other branches also use this airfield, including the United States Coast Guard. Pilots that use this airfield find it to be one of the most demanding airbases in the US, known for its high winds and dangerous terrain surrounding the runway.
The airfield is home to the United States Navy SEALs training facilities located north of the runways.
Fauna and flora 
The San Clemente Island Loggerhead Shrike is an endangered species that the Navy is taking steps to protect. The San Clemente Island Fox is an indigenous species. Feral goats roamed the island for centuries, reaching a population of 11,000 in 1972, when their effect on indigenous species was realized. By 1980 the population had been reduced to 4,000. A plan for shooting remaining goats was blocked in court by the Fund for Animals, so the goats were removed with nets and helicopters. The San Clemente Goat is a recognized breed of domestic goat. The coves around the island are visited by snorkelers attracted by the abundant sea life, including sea lions, spiny lobsters, hydrocoral and kelp forests.
The flora of the island includes some plant species found nowhere else in the world. These endemic species include the wildflowers San Clemente Island brodiaea, San Clemente Island triteleia, San Clemente Island woodland star, and San Clemente Island Indian paintbrush, and the shrubs San Clemente Island bushmallow and Blair's wirelettuce. A unique subspecies of toyon, ssp. macrocarpa, also grows here, as do two rare subspecies of the royal larkspur.
Government and infrastructure 
- Block Group 2, Census Tract 5991, Los Angeles County
- Holder, Fredrick (1910). The Channel islands of California: a book for the angler, sportsman, and tourist. Stationers' Hall London England: A.C McClurg & Co. p. 283.
- Kelsey, Harry (1986). Juan Rodriguez Cabrillo. San Marino: The Huntington Library.
- Webb, Robert (1988). On the Northwest: Commercial Whaling in the Pacific Northwest 1790–1967. University of British Columbia Press. ISBN 0-7748-0292-8.
- Pacific Fisherman (Vol. 24, 1926); Science, Vol. 64 (July 2, 1926 issue); Animal Bulletin: New York Zoological Society, Vols. 29-30, 1926; The Federal Reporter, 1988; American Maritime Cases, (Vol. 2, 1931).
- Townsend, Charles Haskens. 1930. "Twentieth Century Whaling". Bull. New York Zool. Soc., Vol. 33, No. 1; California Fish and Game, Fisheries (1930); Pacific Fisherman (Vols. 28-29, 1930-31).
- Pacific Fisherman (Vol. 31, 1933).
- Nial O'Malley Keyes, Blubber Ship (1939); Andrew R. Boone, Killer Ships of the Whaling Fleet (Popular Science, August 1935); Pacific Fisherman (Vol. 35, 1937).
- Rice, Dale W. The Blue Whales of the Southeastern North Pacific Ocean (AFSC Quarterly Report, 1992).
- C. Michael Hogan, (2008) Toyon (Heteromeles arbutifolia), GlobalTwitcher, ed. N. Stromberg 
- Center for Plant Conservation: Delphinium variegatum ssp. thornei
- "Avalon Station." Los Angeles County Sheriff's Department. Retrieved on January 21, 2010.
|Wikimedia Commons has media related to: San Clemente Island|
- San Clemente Island
- San Clemente Loggerhead Shrike
- Rocket launches at San Clemente
- A very long thesis about the historical geography of San Clemente Island that was funded by the U.S Navy