Baja California, estado (state), northwestern Mexico, bounded to the north by the United States (California and Arizona), to the east by the state of Sonora and the Gulf of California (Sea of Cortez), to the west by the Pacific Ocean, and to the south by the state of Baja California Sur. Its capital city, Mexicali, lies on the U.S.-Mexico border, opposite Calexico, California.
The state occupies the northern half of the Baja California peninsula and consists of rugged granitic mountains, the Sierra de Juárez and the Sierra San Pedro Mártir. Much of the state is occupied by a westward extension of the Sonoran Desert. Coastal plains are narrow except in the extreme northeast, where the Colorado River has formed a delta. However, the Colorado is now used so heavily upstream (mainly to supply crop irrigation and the population centres north of the border) that its remaining waters typically evaporate or seep into the desert before reaching the gulf.
Although the state of Baja California has long been inhabited, settlement of the area has been sparse. The peninsula remained in Spanish possession until 1822, the year after Mexico gained its independence. In 1887 the peninsula was divided into two federal districts; the first capital of northern Baja California was at Ensenada. The district was redesignated as a federal territory in 1931 and became a state in 1952. The name was changed to Baja California Norte in 1974 to distinguish it from the newly created state of Baja California Sur, but by 1979 it was again officially called Baja California.
State government is headed by a governor elected to a single six-year term. Members of the unicameral House of Deputies serve terms of three years. The legislature can levy taxes, but in reality the state depends on the federal government for most of its revenue. Baja California is divided into five local governmental units called municipios (municipalities), each of which is headquartered in its largest town.
Baja California’s proximity to U.S. markets and the development of maquiladoras (export-oriented assembly plants) have spurred rapid growth. Implementation of the North American Free Trade Agreement in 1994 intensified the state’s economic ties with the United States. Tijuana, ideally situated just south of San Diego, California, is the leading maquiladora centre, followed by Mexicali and Tecate. Major manufactures include electronics, textiles, plastics, metal products, automobile components, paper, beverages, and processed foods. The state’s agriculture and industry attract large numbers of immigrants from other Mexican states and Central America. Baja California has one of Mexico’s largest fishing industries, which is centred on Ensenada, one of the country’s busiest ports.
Tourism is also important, notably because of the large number of short-term visitors from California. The beaches at Rosarito are popular with tourists, and Tecate has a famous brewery. Islands and coastal areas in the Gulf of California that belong to Baja California are part of a larger gulfwide UNESCO World Heritage site designated in 2005.
For centuries the various areas of the peninsula were isolated. By the mid-1970s, however, railroads and highways had been built between its principal cities. A major road to Baja California Sur originates at Tijuana and extends southward for some 1,000 miles (1,600 km). International airports are located at Mexicali and Tijuana. Baja California is a popular point of departure for migration to the United States. In addition, the border area has a reputation for international drug trafficking. Area 26,997 square miles (69,921 square km). Pop. (2020) 3,769,020.