The city was first sighted in the year 1542 by the Spanish explorer Juan Rodríguez Cabrillo, back then, the settlement was still known as San Miguel, and was later renamed for the Spanish monk San Diego de Alcalá de Henares in 1602 by Sebastián Vizcaíno. Back in the day, in the city of San Diego in the year 1769, a fort and mission were established for the area, having it expanded and establishing an official military post, turning it into an actual settlement.
Back then, the settlement was confined inside the presidio walls until the 1820s when residents began to build the area known as Old Town. In the year 1834, the control of the mission was assumed by Mexico, and the small settlement was officially recognized as a town, still under Mexico. The U.S then acquired now-known California in the year 1846.
San Diego was actually the very first area that Europeans settled in California, earning its rightful name of "the birthplace of California". Later on, San Diego officially became part of the U.S. in 1848, and the town was named the county seat of San Diego County when California was granted statehood in 1850.
Although the city itself remained to be a small city for some time, the city then experienced rather rapid growth within the 1880s when it established several military facilities. The growth of the city was also further boosted right after World War II as there were countless companies and boosters that laid the basis for an economy based today on the military, defense industries, biotech, tourism, international trade, and manufacturing.
Aside from that, it is also worth noting that the new city of San Diego was laid out 3 miles south of Old Town by businessman Alonzo E. Horton in 1867, having its growth ensured by the promotion of its salubrious climate and the arrival of the Santa Fe Railway in 1885. With all the new developments and project developments in the city, San Diego eventually became the eighth largest city in the country and forms the heart of the larger San Diego metropolitan area.
After some time within the 1900s, the city of San Diego experienced some more fast growth as a town, having its population rise from less than 20,000 to a whopping 200,000 by the year 1940. As of that time, the city’s main traditional economic base was agriculture, mainly citrus, and fishing. Eventually, their economic bases were further advanced and expanded with the development and introduction of manufacturing, such as aircraft, as well as shipping, with the opening of the Panama Canal in 1914.
Mainly, with the enormous economic boon, the new waterway gave the city, it was celebrated all throughout 1915 to 1916 with the Panama-California Exposition. Naturally, the contributions of the increasing military presence are not something to scoff at considering the great importance that the U.S. Navy played for the city’s development.
Furthermore, major installations established there included Naval Base Point Loma (1898; originally a U.S. Army fort), the Marine Corps Recruit Depot (1911), Marine Corps Air Station Miramar (originally the Army’s Camp Kearney), and Naval Air Station North Island (both 1917), Naval Base San Diego (1919), and Naval Amphibious Base Coronado (1943).
After World War II, San Diego’s land area and the population nearly quadrupled between 1950 and 2000. The industry expanded to include electronics, aerospace technology, and shipbuilding. In addition, the area’s equable climate, which had been a significant factor in attracting manufacturing and the military, drew growing numbers of retirees as well as tourists.