San Diego is a major city in California, United States. It is in San Diego County, on the coast of the Pacific Ocean in Southern California, approximately 120 miles (190 km) south of Los Angeles and immediately adjacent to the border with Mexico.
With an estimated population of 1,419,516 as of July 1, 2017, San Diego is the eighth-largest city in the United States and second-largest in California. It is part of the San Diego–Tijuana conurbation, the second-largest transborder agglomeration between the US and a bordering country after Detroit–Windsor, with a population of 4,922,723 people. The city is known for its mild year-round climate, natural deep-water harbor, extensive beaches, long association with the United States Navy, and recent emergence as a healthcare and biotechnology development center.
San Diego has been called “the birthplace of California”. Historically home to the Kumeyaay people, it was the first site visited by Europeans on what is now the West Coast of the United States. Upon landing in San Diego Bay in 1542, Juan Rodríguez Cabrillo claimed the area for Spain, forming the basis for the settlement of Alta California 200 years later. The Presidio and Mission San Diego de Alcalá, founded in 1769, formed the first European settlement in what is now California. In 1821, San Diego became part of the newly independent Mexico, which reformed as the First Mexican Republic two years later. California became part of the United States in 1848 following the Mexican–American War and was admitted to the union as a state in 1850.
The city is the seat of San Diego County and is the economic center of the region as well as the San Diego–Tijuana metropolitan area. San Diego’s main economic engines are military and defense-related activities, tourism, international trade, and manufacturing. The presence of the University of California, San Diego (UCSD), with the affiliated UCSD Medical Center, has helped make the area a center of research in biotechnology.
The city had a population of 1,307,402 according to the 2010 census, distributed over a land area of 372.1 square miles (963.7 km2). The urban area of San Diego extends beyond the administrative city limits and had a total population of 2,956,746, making it the third-largest urban area in the state, after that of the Los Angeles metropolitan area and San Francisco metropolitan area. They, along with the Riverside–San Bernardino, form those metropolitan areas in California larger than the San Diego metropolitan area, which had a total population of 3,095,313 at the 2010 census.
The 2010 population represents an increase of just under 7% from the 1,223,400 people, 450,691 households, and 271,315 families reported in 2000. The estimated city population in 2009 was 1,306,300. The population density was 3,771.9 inhabitants per square mile (1,456.3/km2). The racial makeup of San Diego was 58.9% White, 6.7% African American, 0.6% Native American, 15.9% Asian (5.9% Filipino, 2.7% Chinese, 2.5% Vietnamese, 1.3% Indian, 1.0% Korean, 0.7% Japanese, 0.4% Laotian, 0.3% Cambodian, 0.1% Thai). 0.5% Pacific Islander (0.2% Guamanian, 0.1% Samoan, 0.1% Native Hawaiian), 12.3% from other races, and 5.1% from two or more races. The ethnic makeup of the city was 28.8% Hispanic or Latino (of any race); 24.9% of the total population were Mexican American, and 0.6% were Puerto Rican. Median age of Hispanics was 27.5 years, compared to 35.1 years overall and 41.6 years among non-Hispanic whites; Hispanics were the largest group in all ages under 18, and non-Hispanic whites constituted 63.1% of population 55 and older.
As of December 2012, San Diego has the third-largest homeless population in the United States; the city’s homeless population has the largest percentage of homeless veterans in the nation. The population of homeless veterans in San Diego has been reduced to 1,150 people in 2016, from 2,100 in 2009.
In 2000 there were 451,126 households, out of which 30.2% had children under the age of 18 living with them, 44.6% were married couples living together, 11.4% had a female householder with no husband present, and 39.8% were non-families. Households made up of individuals account for 28.0%, and 7.4% had someone living alone who was 65 years of age or older. The average household size was 2.61, and the average family size was 3.30.
The U.S. Census Bureau reported that in 2000, 24.0% of San Diego residents were under 18, and 10.5% were 65 and over. As of 2011 the median age was 35.6; more than a quarter of residents were under age 20 and 11% were over age 65. Millennials (ages 18 through 34) constitute 27.1% of San Diego’s population, the second-highest percentage in a major U.S. city. The San Diego County regional planning agency, SANDAG, provides tables and graphs breaking down the city population into five-year age groups.