Santa Catalina Island (Tongva: Pimuu'nga or Pimu; Spanish: Isla Santa Catalina) is a rocky island off the coast of Southern California in the Gulf of Santa Catalina. The island name is often shortened to Catalina Island or just Catalina. The island is 22 mi (35 km) long and 8 mi (13 km) across at its greatest width. The island is located about 29 mi (47 km) south-southwest of Long Beach, California. The highest point on the island is Mount Orizaba (2,097 ft or 639 m). Geologically, Santa Catalina is part of the Channel Islands of California archipelago and is the easternmost of the Channel Islands. Politically, Catalina Island is part of Los Angeles County in District 4. Most of the land on the island is unincorporated (governed by the county).

Catalina was originally inhabited and used by many different Southern California Tribes, including the Tongva, who called the island Pimuu'nga or Pimu and referred to themselves as Pimugnans or Pimuvit. The first Europeans to arrive on Catalina claimed it for the Spanish Empire. Over the years, territorial claims to the island transferred it to Mexico and then to the United States. During this time, the island was sporadically used for smuggling, otter hunting, and gold digging, before successfully being developed into a tourist destination by chewing gum magnate William Wrigley Jr. beginning in the 1920s. Since the 1970s, most of the island has been administered by the Catalina Island Conservancy.

Its total population in the 2010 census was 4,096 people, 90 percent of whom live in the island's only incorporated city, Avalon. The second center of population is the unincorporated village of Two Harbors at the island's isthmus. Development also occurs at the smaller settlements of Rancho Escondido and Middle Ranch. The remaining population is scattered over the island between the two population centers.

Juan Rodríguez Cabrillo; March 13, 1499 – January 3, 1543) was a maritime explorer best known for investigations of the West Coast of North America, undertaken on behalf of the Spanish Empire. He was the first European to explore present-day California, navigating along the coast of California in 1542–1543.