Baja California (Span.: bäˈhä kälēfōrˈnyä) [key] or Lower California, peninsula, c.760 mi (1,220 km) long and from 30 to 150 mi (48–241 km) wide, NW Mexico, separating the Gulf of California from the Pacific Ocean. The peninsula is divided at lat. 28° N into the state of Baja California in the north, and the state of Baja California Sur in the south. Except for two large coastal plains on the Pacific side, the peninsula consists largely of rugged mountain ranges averaging 5,000 ft (1,524 m), with one peak, San Pedro Martir, more than 10,000 ft (3,048 m) high. The land is generally desolate and arid. The only naturally cultivable areas are isolated mountain valleys. However, irrigation systems on the Colorado River have made possible the development of a rich farming area around Mexicali, and the region is a leading national producer of cotton and wheat. There are fisheries and fish canneries at Ensenada, which is also developing as a resort. Wealthy Mexicans, who have bought large estates and established resort ranches on the scenic coasts, have done much to stir tourist interest in regions other than the border towns and to open up hitherto inaccessible areas. Hunting and deep-sea fishing are favorite sports. Baja California Sur is not economically prosperous, although tourism is developing rapidly, particularly around Los Cabos. The peninsula and surrounding waters are a paradise also for naturalists and archaeologists, offering unparalleled opportunities for the study of marine life, plants and animals, and archaeological artifacts. Since 1962 remarkable mural paintings have been discovered in many caves there. Perhaps the most important development for the northern state is the growth of U.S.- and foreign-owned factories (maquiladoras) in the border areas. A large, rapidly expanding population and low labor costs have led to the opening of many maquiladoras in Baja California.
The coasts were first explored by Francisco de Ulloa and other Spaniards in the 1530s. Attempts to colonize the interior were largely unsuccessful. U.S. forces occupied (1847–48) Baja California during the Mexican War, and William Walker attempted (1853–54) to wrest it from Mexico in his first disastrous filibustering expedition. In 1911 the area was the scene of an abortive uprising against Porfirio Díaz—the so-called desert revolution led by Ricardo Flores Magón, a liberal anarchist, who was a precursor of Francisco Madero and Emiliano Zapata.
See J. Steinbeck, The Log from the Sea of Cortez (1951); H. Crosby, Last of the Californias (1981); D. Polk, The Island of California (1991).