San Diego (volcano)

; , ) is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the eighth-most populous city in the United States, the second-most populous city in California and the seat of San Diego County, the fifth-most populous county in the United States, with 3,286,069 estimated residents . The city is known for its mild year-round Mediterranean climate, natural deep-water harbor, extensive beaches and parks, long association with the United States Navy, and recent emergence as a healthcare and biotechnology development center. San Diego is the second-largest city in California after Los Angeles.

Historically home to the Kumeyaay Native Americans, San Diego has been referred to as the Birthplace of California, since it was the first site visited and settled by Europeans on what is now the U.S. West Coast. 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 declared Mexican Empire, which reformed as the First Mexican Republic two years later. California was conquered by the U.S. in 1848 following the Mexican–American War and was admitted to the union as a state in 1850.

San Diego's main economic engines are military and defense-related activities, tourism, international trade, research, and manufacturing. The city is the economic center of the San Diego–Tijuana conurbation, the second-most populous transborder metropolitan area in the Western Hemisphere (after Detroit–Windsor), home to an estimated 4,922,723 people . The primary border crossing between San Diego and Tijuana, the San Ysidro Port of Entry, is the busiest international land border crossing in the world outside of Asia ( fourth-busiest overall). The city's airport, San Diego International Airport, is the busiest single-runway airport in the world.

History

Pre-colonial period

What has been referred to as the San Dieguito complex was established in the area at least 9,000 years ago. The Kumeyaay may have culturally evolved from this complex or migrated into the area around 1000 C.E. Archaeologist Malcolm Rogers hypothesized that the early cultures of San Diego were separate from the Kumeyaay, yet this claim is disputed, with others noting that it does not account for cultural evolution. Rogers later reevaluated his claims, yet they were influential in shaping historical tellings of early San Diego history.

The Kumeyaay established villages scattered across the region, including the village of Kosa'aay which was the Kumeyaay village that the future settlement of San Diego would stem from in today's Old Town. The village of Kosa'aay was made up of thirty to forty families living in pyramid-shaped housing structures and was supported by a freshwater spring from the hillsides.

Spanish period

The first European to visit the region was explorer Juan Rodríguez Cabrillo, sailing under the flag of Castile but possibly born in Portugal. Sailing his flagship ''San Salvador'' from Navidad, New Spain, Cabrillo claimed the bay for the Spanish Empire in 1542, and named the site "San Miguel". In November 1602, Sebastián Vizcaíno was sent to map the California coast. Arriving on his flagship ''San Diego'', Vizcaíno surveyed the harbor and what are now Mission Bay and Point Loma and named the area for the Catholic Saint Didacus, a Spaniard more commonly known as ''San Diego de Alcalá''. On November 12, 1602, the first Christian religious service of record in Alta California was conducted by Friar Antonio de la Ascensión, a member of Vizcaíno's expedition, to celebrate the feast day of San Diego.

The permanent European colonization of both California and San Diego began in 1769 with the arrival of four contingents of Spaniards from New Spain and the Baja California peninsula. Two seaborne parties reached San Diego Bay: the ''San Carlos'', under Vicente Vila and including as notable members the engineer and cartographer Miguel Costansó and the soldier and future governor Pedro Fages, and the ''San Antonio'', under Juan Pérez. An initial overland expedition to San Diego from the south was led by the soldier Fernando Rivera and included the Franciscan missionary, explorer, and chronicler Juan Crespí, followed by a second party led by the designated governor Gaspar de Portolà and including the mission president (and now saint) Junípero Serra.

In May 1769, Portolà established the Fort Presidio of San Diego on a hill near the San Diego River above the Kumeyaay village of Cosoy, which would later become incorporated into the Spanish settlement, making it the first settlement by Europeans in what is now the state of California. In July of the same year, Mission San Diego de Alcalá was founded by Franciscan friars under Serra. The mission became a site for a Kumeyaay revolt in 1775, which forced the mission to relocate up the San Diego River. By 1797, the mission boasted the largest native population in Alta California, with over 1,400 neophytes living in and around the mission proper. Mission San Diego was the southern anchor in Alta California of the historic mission trail El Camino Real. Both the Presidio and the Mission are National Historic Landmarks.

Mexican period

In 1821, Mexico won its independence from Spain, and San Diego became part of the Mexican territory of Alta California. In 1822, Mexico began its attempt to extend its authority over the coastal territory of Alta California. The fort on Presidio Hill was gradually abandoned, while the town of San Diego grew up on the level land below Presidio Hill. The Mission was secularized by the Mexican government in 1834, and most of the Mission lands were granted to former soldiers. The 432 residents of the town petitioned the governor to form a pueblo, and Juan María Osuna was elected the first ''alcalde'' ("municipal magistrate"), defeating Pío Pico in the vote. Beyond the town, Mexican land grants expanded the number of California ranchos that modestly added to the local economy. (See, ''List of pre-statehood mayors of San Diego''.)

However, San Diego had been losing population throughout the 1830s, due to increasing tension between the settlers and the indigenous Kumeyaay and in 1838 the town lost its pueblo status because its size dropped to an estimated 100 to 150 residents. The ranchos in the San Diego region would face Kumeyaay raids in the late 1830s and the town itself would face raids in the 1840s.

Americans gained an increased awareness of California, and its commercial possibilities, from the writings of two countrymen involved in the often officially forbidden, to foreigners, but economically significant hide and tallow trade, where San Diego was a major port and the only one with an adequate harbor: William Shaler's "Journal of a Voyage Between China and the North-Western Coast of America, Made in 1804" and Richard Henry Dana's more substantial and convincing account, of his 1834–36 voyage, the classic ''Two Years Before the Mast''.

In 1846, the United States went to war against Mexico and sent a naval and land expedition to conquer Alta California. At first, they had an easy time of it, capturing the major ports including San Diego, but the Californios in southern Alta California struck back. Following the successful revolt in Los Angeles, the American garrison at San Diego was driven out without firing a shot in early October 1846. Mexican partisans held San Diego for three weeks until October 24, 1846, when the Americans recaptured it. For the next several months the Americans were blockaded inside the pueblo. Skirmishes occurred daily and snipers shot into the town every night. The Californios drove cattle away from the pueblo hoping to starve the Americans and their Californio supporters out. On December 1, the American garrison learned that the dragoons of General Stephen W. Kearney were at Warner's Ranch. Commodore Robert F. Stockton sent a mounted force of fifty under Captain Archibald Gillespie to march north to meet him. Their joint command of 150 men, returning to San Diego, encountered about 93 Californios under Andrés Pico.

In the ensuing Battle of San Pasqual, fought in the San Pasqual Valley which is now part of the city of San Diego, the Americans suffered their worst losses in the campaign. Subsequently, a column led by Lieutenant Gray arrived from San Diego, rescuing Kearny's battered and blockaded command. Stockton and Kearny went on to recover Los Angeles and force the capitulation of Alta California with the "Treaty of Cahuenga" on January 13, 1847. As a result of the Mexican–American War of 1846–48, the territory of Alta California, including San Diego, was ceded to the United States by Mexico, under the terms of the Treaty of Guadalupe Hidalgo in 1848. The Mexican negotiators of that treaty tried to retain San Diego as part of Mexico, but the Americans insisted that San Diego was "for every commercial purpose of nearly equal importance to us with that of San Francisco," and the Mexican–American border was eventually established to be one league south of the southernmost point of San Diego Bay, so as to include the entire bay within the United States.

American period

The state of California was admitted to the United States in 1850. That same year San Diego was designated the seat of the newly established County of San Diego and was incorporated as a city. Joshua H. Bean, the last alcalde of San Diego, was elected the first mayor. Two years later the city was bankrupt; the California legislature revoked the city's charter and placed it under control of a board of trustees, where it remained until 1889. A city charter was reestablished in 1889, and today's city charter was adopted in 1931.

The original town of San Diego was located at the foot of Presidio Hill, in the area which is now Old Town San Diego State Historic Park. The location was not ideal, being several miles away from navigable water at its port at La Playa. In 1850, William Heath Davis promoted a new development by the bay shore called "New San Diego", several miles south of the original settlement; however, for several decades the new development consisted only of a pier, a few houses and an Army depot for the support of Fort Yuma. After 1854, the fort became supplied by sea and by steamboats on the Colorado River and the depot fell into disuse. From 1857 to 1860, San Diego became the western terminus of the San Antonio-San Diego Mail Line, the earliest overland stagecoach and mail operation from the Eastern United States to California, coming from Texas through New Mexico Territory in less than 30 days.Basil C. Pearce
"The Jackass Mail—San Antonio and San Diego Mail Line"
''San Diego Historical Society Quarterly'', Spring 1969, Volume 15, Number 2

In the late 1860s, Alonzo Horton promoted a move to the bayside area, which he called "New Town" and which became Downtown San Diego. Horton promoted the area heavily, and people and businesses began to relocate to New Town because its location on San Diego Bay was convenient to shipping. New Town soon eclipsed the original settlement, known to this day as Old Town, and became the economic and governmental heart of the city. Still, San Diego remained a relative backwater town until the arrival of a railroad connection in 1878. In 1884–1886, John J. Montgomery made the first controlled flights by an American in a heavier-than-air unpowered glider just south of San Diego at Otay Mesa, helping to pioneer a new science of aerodynamics.

In 1912, San Diego was the site of a free speech fight between the Industrial Workers of the World and the city government who passed an ordinance forbidding the freedom of speech along an area of "Soapbox Row" that led to civil disobedience, vigilantism, police violence, the abduction of Emma Goldman's husband Ben Reitman and multiple riots. San Diego's proximity to Tijuana during the Mexican Revolution made this one of the most significant free speech fights during the Wobbly era.

In 1916, the neighborhood of Stingaree, the original home of San Diego's first Chinatown and "Soapbox Row", was demolished by anti-vice campaigners to make way for the Gaslamp Quarter.

In the early part of the 20th century, San Diego hosted the World's Fair twice: the Panama-California Exposition (1915) and the California Pacific International Exposition in 1935. Both expositions were held in Balboa Park, and many of the Spanish/Baroque-style buildings that were built for those expositions remain to this day as central features of the park. The buildings were intended to be temporary structures, but most remained in continuous use until they progressively fell into disrepair. Most were eventually rebuilt, using castings of the original façades to retain the architectural style. The menagerie of exotic animals featured at the 1915 exposition provided the basis for the San Diego Zoo. During the 1950s there was a citywide festival called Fiesta del Pacifico highlighting the area's Spanish and Mexican past. In the 2010s there was a proposal for a large-scale celebration of the 100th anniversary of Balboa Park, but the plans were abandoned when the organization tasked with putting on the celebration went out of business.

The southern portion of the Point Loma peninsula was set aside for military purposes as early as 1852. Over the next several decades the Army set up a series of coastal artillery batteries and named the area Fort Rosecrans. Significant U.S. Navy presence began in 1901 with the establishment of the Navy Coaling Station in Point Loma, and expanded greatly during the 1920s. By 1930, the city was host to Naval Base San Diego, Naval Training Center San Diego, San Diego Naval Hospital, Camp Matthews, and Camp Kearny (now Marine Corps Air Station Miramar). The city was also an early center for aviation: as early as World War I, San Diego was proclaiming itself "The Air Capital of the West". The city was home to important airplane developers and manufacturers like Ryan Airlines (later Ryan Aeronautical), founded in 1925, and Consolidated Aircraft (later Convair), founded in 1923. Charles A. Lindbergh's plane The Spirit of St. Louis was built in San Diego in 1927 by Ryan Airlines.

During World War II, San Diego became a major hub of military and defense activity, due to the presence of so many military installations and defense manufacturers. The city's population grew rapidly during and after World War II, more than doubling between 1930 (147,995) and 1950 (333,865).Moffatt, Riley. ''Population History of Western U.S. Cities & Towns, 1850–1990''. Lanham: Scarecrow, 1996, 54. During the final months of the war, the Japanese had a plan to target multiple U.S. cities for biological attack, starting with San Diego. The plan was called "Operation Cherry Blossoms at Night" and called for kamikaze planes filled with fleas infected with plague (''Yersinia pestis'') to crash into civilian population centers in the city, hoping to spread plague in the city and effectively kill tens of thousands of civilians. The plan was scheduled to launch on September 22, 1945, but was not carried out because Japan surrendered five weeks earlier.

After World War II, the military continued to play a major role in the local economy, but post-Cold War cutbacks took a heavy toll on the local defense and aerospace industries. The resulting downturn led San Diego leaders to seek to diversify the city's economy by focusing on research and science, as well as tourism.

From the start of the 20th century through the 1970s, the American tuna fishing fleet and tuna canning industry were based in San Diego, "the tuna capital of the world". San Diego's first tuna cannery was founded in 1911, and by the mid-1930s the canneries employed more than 1,000 people. A large fishing fleet supported the canneries, mostly staffed by immigrant fishermen from Japan, and later from the Portuguese Azores and Italy whose influence is still felt in neighborhoods like Little Italy and Point Loma. Due to rising costs and foreign competition, the last of the canneries closed in the early 1980s.

Downtown San Diego was in decline in the 1960s and 1970s, but experienced some urban renewal since the early 1980s, including the opening of Horton Plaza, the revival of the Gaslamp Quarter, and the construction of the San Diego Convention Center; Petco Park opened in 2004. Outside of downtown, San Diego annexed large swaths of land and for suburban expansion to the north and control of the San Ysidro Port of Entry.

As the Cold War ended, the military shrank and so did defense spending. San Diego has since become a center of the emerging biotech industry and is home to telecommunications giant Qualcomm. San Diego had also grown in the tourism industry with the popularity of attractions such as the San Diego Zoo, SeaWorld San Diego, and Legoland California in Carlsbad.

Geography

According to SDSU professor emeritus Monte Marshall, San Diego Bay is "the surface expression of a north-south-trending, nested graben". The Rose Canyon and Point Loma fault zones are part of the San Andreas Fault system. About east of the bay are the Laguna Mountains in the Peninsular Ranges, which are part of the backbone of the American continents.

The city lies on approximately 200 deep canyons and hills separating its mesas, creating small pockets of natural open space scattered throughout the city and giving it a hilly geography. Traditionally, San Diegans have built their homes and businesses on the mesas, while leaving the urban canyons relatively wild. Thus, the canyons give parts of the city a segmented feel, creating gaps between otherwise proximate neighborhoods and contributing to a low-density, car-centered environment. The San Diego River runs through the middle of San Diego from east to west, creating a river valley that serves to divide the city into northern and southern segments. During the historic period and presumably earlier as well, the river has shifted its flow back and forth between San Diego Bay and Mission Bay, and its fresh water was the focus of the earliest Spanish explorers. Miguel Costansó, a cartographer, wrote in 1769, "When asked by signs where the watering-place was, the Indians pointed to a grove which could be seen at a considerable distance to the northeast, giving to understand that a river or creek flowed through it, and that they would lead our men to it if they would follow.""Expeditions by Sea" ''The Explorers''. Trans. Richard F. Pourade. La Jolla: Copley, 1960. 64–72. That river was the San Diego River. Several reservoirs and Mission Trails Regional Park also lie between and separate developed areas of the city.

Notable peaks within the city limits include Cowles Mountain, the highest point in the city at ; Black Mountain at ; and Mount Soledad at . The Cuyamaca Mountains and Laguna Mountains rise to the east of the city, and beyond the mountains are desert areas. The Cleveland National Forest is a half-hour drive from downtown San Diego. Numerous farms are found in the valleys northeast and southeast of the city.

In its 2013 ParkScore ranking, The Trust for Public Land reported that San Diego had the 9th-best park system among the 50 most populous U.S. cities. ParkScore ranks city park systems by a formula that analyzes acreage, access, and service and investment.

Climate

San Diego has one of the top-ten best climates in the United States, according to the ''Farmers' Almanac'' and has one of the two best summer climates in the country as scored by The Weather Channel. Under the Köppen–Geiger climate classification system, the San Diego area has been variously categorized as having either a semi-arid climate (''BSh'' in the original classification and ''BSkn'' in modified Köppen classification with the n denoting summer fog) or a hot-summer Mediterranean climate (''Csa''). San Diego's climate is characterized by warm, dry summers and mild winters, with most of the annual precipitation falling between December and March. The city has a mild climate year-round, with an average of 201 days above and low rainfall ( annually).

The climate in San Diego, like most of Southern California, often varies significantly over short geographical distances, resulting in microclimates. In San Diego, this is mostly because of the city's topography (the Bay, and the numerous hills, mountains, and canyons). Frequently, particularly during the "May gray/ June gloom" period, a thick "marine layer" cloud cover keeps the air cool and damp within a few miles of the coast, but yields to bright cloudless sunshine approximately inland. Sometimes the June gloom lasts into July, causing cloudy skies over most of San Diego for the entire day. Even in the absence of June gloom, inland areas experience much more significant temperature variations than coastal areas, where the ocean serves as a moderating influence. Thus, for example, downtown San Diego averages January lows of and August highs of . The city of El Cajon, just inland from downtown San Diego, averages January lows of and August highs of .

The average surface temperature of the water at Scripps Pier in the California Current has increased by almost since 1950, according to scientists at Scripps Institution of Oceanography. Additionally, the mean minimum is now above , putting San Diego in hardiness zone 11, with the last freeze having occurred many decades ago.

Annual rainfall along the coast averages and the median is . The months of December through March supply most of the rain, with February the only month averaging or more. The months of May through September tend to be almost completely dry. Although there are few wet days per month during the rainy period, rainfall can be heavy when it does fall. Rainfall is usually greater in the higher elevations of San Diego; some of the higher areas can receive per year. Variability from year to year can be dramatic: in the wettest years of 1883/1884 and 1940/1941, more than fell, whilst in the driest years there was as little as . The wettest month on record is December 1921 with .

Snow in the city is so rare that it has been observed only six times in the century-and-a-half that records have been kept. In 1949 and 1967, snow stayed on the ground for a few hours in higher locations like Point Loma and La Jolla. The other three occasions, in 1882, 1946, and 1987, involved flurries but no accumulation. On February 21, 2019, snow fell and accumulated in residential areas of the city, but none fell in the downtown area.

Ecology

Like much of Southern California, the majority of San Diego's current area was originally occupied on the west by coastal sage scrub and on the east by chaparral, plant communities made up mostly of drought-resistant shrubs. The steep and varied topography and proximity to the ocean create a number of different habitats within the city limits, including tidal marsh and canyons. The chaparral and coastal sage scrub habitats in low elevations along the coast are prone to wildfire, and the rates of fire increased in the 20th century, due primarily to fires starting near the borders of urban and wild areas.

San Diego's broad city limits encompass a number of large nature preserves, including Torrey Pines State Reserve, Los Peñasquitos Canyon Preserve, and Mission Trails Regional Park. Torrey Pines State Reserve and a coastal strip continuing to the north constitute one of only two locations where the rare species of Torrey Pine, ''Pinus torreyana'', is found.
Due to the steep topography that prevents or discourages building, along with some efforts for preservation, there are also a large number of canyons within the city limits that serve as nature preserves, including Switzer Canyon, Tecolote Canyon Natural Park, and Marian Bear Memorial Park in San Clemente Canyon, as well as a number of small parks and preserves.

San Diego County has one of the highest counts of animal and plant species that appear on the endangered list of counties in the United States. Because of its diversity of habitat and its position on the Pacific Flyway, San Diego County has recorded 492 different bird species, more than any other region in the country. San Diego always scores high in the number of bird species observed in the annual Christmas Bird Count, sponsored by the Audubon Society, and it is known as one of the "birdiest" areas in the United States.

San Diego and its backcountry suffer from periodic wildfires. In October 2003, San Diego was the site of the Cedar Fire, at that time the largest wildfire in California over the past century. The fire burned , killed 15 people, and destroyed more than 2,200 homes. In addition to damage caused by the fire, smoke resulted in a significant increase in emergency room visits due to asthma, respiratory problems, eye irritation, and smoke inhalation; the poor air quality caused San Diego County schools to close for a week. Wildfires four years later destroyed some areas, particularly within Rancho Bernardo, as well as the nearby communities of Rancho Santa Fe and Ramona.

Neighborhoods

The City of San Diego recognizes 52 individual areas as Community Planning Areas. Within a given planning area there may be several distinct neighborhoods. Altogether the city contains more than 100 identified neighborhoods.

Downtown San Diego is located on San Diego Bay. Balboa Park encompasses several mesas and canyons to the northeast, surrounded by older, dense urban communities including Hillcrest and North Park. To the east and southeast lie City Heights, the College Area, and Southeast San Diego. To the north lies Mission Valley and Interstate 8. The communities north of the valley and freeway, and south of Marine Corps Air Station Miramar, include Clairemont, Kearny Mesa, Tierrasanta, and Navajo. Stretching north from Miramar are the northern suburbs of Mira Mesa, Scripps Ranch, Rancho Peñasquitos, and Rancho Bernardo. The far northeast portion of the city encompasses Lake Hodges and the San Pasqual Valley, which holds an agricultural preserve. Carmel Valley and Del Mar Heights occupy the northwest corner of the city. To their south are Torrey Pines State Reserve and the business center of the Golden Triangle. Further south are the beach and coastal communities of La Jolla, Pacific Beach, Mission Beach, and Ocean Beach. Point Loma occupies the peninsula across San Diego Bay from downtown. The communities of South San Diego (an Exclave), such as San Ysidro and Otay Mesa, are located next to the Mexico–United States border, and are physically separated from the rest of the city by the cities of National City and Chula Vista. A narrow strip of land at the bottom of San Diego Bay connects these southern neighborhoods with the rest of the city.
neighborhoods in San Diego