Terminal Island, historically known as Isla Raza de Buena Gente, is a largely artificial island located in Los Angeles County, California, between the neighborhoods of Wilmington and San Pedro in the city of Los Angeles, and the city of Long Beach. Terminal Island is roughly split between the Port of Los Angeles and Port of Long Beach. Land use on the island is entirely industrial and port-related except for Federal Correctional Institution, Terminal Island.

The original Tongva name for the island is unknown, though Spanish colonizers first named it Isla Raza de Buena Gente and later Rattlesnake Island. It was renamed Terminal Island in 1891.

In 1909, the newly reincorporated Southern California Edison Company decided to build a new steam station to provide reserve capacity and emergency power for the entire Edison system and to enable Edison to shut down some of its small, obsolete steam plants. The site chosen for the new plant was on a barren mudflat known as Rattlesnake Island, today's Terminal Island in the San Pedro Bay. Construction of Plant No. 1 began in 1910.

The land area of Terminal Island has been supplemented considerably from its original size. In 1909 the city of Los Angeles annexed the city of Wilmington. During this time the "Father of the Harbor" Phineas Banning, held deed to roughly 18 acres of land on Rattlesnake Island. Phineas Banning was instrumental in bringing innovative changes to San Pedro Bay and made the first steps towards expansion. Once annexed with the city of Los Angeles the expansion was completed. In the late 1920s, Deadman's Island in the main channel of the Port of Los Angeles was dynamited and dredged away, and the resulting rubble was used to add 62 acres (0.097 sq mi) to Terminal Island's southern tip.

In 1930, the Ford Motor Company built a facility called Long Beach Assembly, having moved earlier operations from Downtown Los Angeles. The factory remained until 1958 when manufacturing operations were moved inland to Pico Rivera.

In 1927, a civilian facility, Allen Field, was established on Terminal Island. The Naval Reserve established a training center at the field and later took complete control, designating the field Naval Air Base San Pedro (also called Reeves Field). In 1941, the Long Beach Naval Station was located adjacent to the airfield. In 1942, the Naval Reserve Training Facility was transferred, and a year later NAB San Pedro's status was downgraded to a Naval Air Station (NAS Terminal Island). Reeves Field as a Naval Air Station was disestablished in 1947, although the adjacent Long Beach Naval Station continued to use Reeves Field as an auxiliary airfield until the late 1990s. A large industrial facility now covers the site of the former Naval Air Station.

Starting in 1906, a Japanese American fishing community became established on Terminal Island in an area known as East San Pedro or Fish Island. Because of the island's relative geographical isolation, its inhabitants developed their own culture and dialect. The dialect, known as "kii-shu ben" (or "Terminal Island lingo"), was a mix of English and the dialect of Kii Province, where many residents originated. Prior to World War II, the island was home to about 3,500 first- and second-generation Japanese Americans.

Like many Japanese immigrants, the initial settlers who came to America were Dekasegi, immigrants who intended to work a short time in the U.S then return to Japan. Many of these immigrants first arrived in Santa Monica, California with the hopes of creating a community there but after their town was burned in 1916, they moved to Terminal Island. Growing fishing interests in San Pedro's White Point and Terminal Island led many Japanese to become sought after due to their skill as fishermen and connections to the canning industry. The first major sign of the community's forming came in the form of the Southern California Japanese Fishermen's Association (SCJFA), a political and social body. On January 26, 1918, their efforts were rewarded with a completed assembly hall for the community.