California

San Diego

3,298,634
2020 population
1850
first census record
18
census records

About San Diego

San Diego, California, first appears in the United States federal census in 1850, when it recorded a population of 798. At the most recent census, in 2020, its population stood at 3,298,634.

The county's recorded population has risen across the decades to its highest level in 2020.

On the ground today, 18 documented military engagements have been recorded within the county, among them Kumeyaay Inter-Group Warfare – San Diego, Kumeyaay Attack on Mission San Diego 1769, Mission San Diego Revolt — 1775, and 161 places are listed on the National Register of Historic Places.

Population by decade

Census YearPopulationChart
20203,298,634
20103,095,313
20002,813,833
19902,498,016
19801,861,846
19701,357,854
19601,033,011
1950556,808
1940289,348
1930209,659
1920112,248
191061,665
190035,090
189034,987
18808,618
18704,951
18604,324
1850798
Source

Population data from the United States decennial census, U.S. Census Bureau (public domain).

Battles & engagements in San Diego

Military engagements that took place in San Diego, California.

Kumeyaay Inter-Group Warfare – San Diego
1300
Kumeyaay Attack on Mission San Diego 1769
1769
Mission San Diego Revolt — 1775
1775
Kumeyaay Uprising – Mission San Diego 1775
1775
Kumeyaay Revolt - Murder of Father Jayme
1775
Battle of San Pasqual — Second Day (December 7)
1846
Battle of San Pasqual (California)
1846
Capture of San Diego
1846
Battle of San Pasqual – Pico's Lancer Charge
1846
San Diego Naval Occupation
1846
Mexican-American War — Battle of San Pasqual
1846
Battle of San Diego Dec 1846
1846
USS Cyane at San Diego
1846
Battle of San Pasqual
1846
Battle of La Mesa – Detail
1847
Mission San Luis Rey Skirmish
1847
Battle of Warner's Ranch
1851
San Pasqual Engagement — Luiseño/Cahuilla
1875

Historic places in San Diego

National Register of Historic Places listings in San Diego, California.

Estudillo House
San Diego
Edgemoor Farm Dairy Barn
Santee
San Luis Rey Mission Church
Oceanside
San Diego Mission Church
San Diego
BERKELEY
San Diego
Santa Fe Depot
San Diego
University Heights Water Storage and Pumping Station Historic District
San Diego
Americanization School
Oceanside
El Prado Complex
San Diego
Spreckels Theatre Building
San Diego
Marine Corps Recruit Depot Historic District
San Diego
Balboa Theatre
San Diego
California Quadrangle
San Diego
Georgia Street Bridge-Caltrans Bridge
San Diego
Initial Point of Boundary Between U.S. and Mexico
San Diego
Mission Brewery
San Diego
Balboa Park
San Diego
City of San Diego Police Headquarters, Jails and Courts
San Diego
Fleming, Guy and Margaret, House
San Diego
Grant, U.S. Hotel
San Diego
Kuchamaa
Tecate
Rosicrucian Fellowship Temple
Oceanside
Rancho Guajome Adobe
Vista
San Diego Armed Services YMCA
San Diego
Browse all Californiahistoric sites ›

Other counties in California

Explore census history and historic records for more California counties.

StanislausSutterTehamaTrinityTulareTuolumneVenturaYoloYubaAlamedaAlpineAmadorButteCalaverasColusaContra CostaDel NorteEl DoradoFresnoGlenn
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Everything a full report reveals about San Diego County, California

This page charts the census history of San Diego County, California. A full Aubrey report for an address here pulls together everything the historical record holds about the ground, from the earliest settlement to the twentieth century:

Overview
An interactive map of the location with historic sites, battles and Native heritage plotted, and its full story era by era.
The Land
The historic sites and place names around the location, and how this land was settled and used.
Geology
The bedrock beneath the site, its age and rock type, reaching back millions of years.
LiDAR Terrain
Laser-scanned terrain that reveals earthworks and old features hidden in the landscape.
Conflict & War
The battles, raids and skirmishes fought near here, across every era of American conflict.
The Civil War
The Civil War on this ground, 1861 to 1865: who held it, and the battles, camps and regiments nearby.
The Soldiers
The men who marched from here in the Civil War, named and traced where the record allows.
Native Heritage
The Native nations who held this land, mapped across time from before European contact to today.
Settlement
Who claimed and held this ground, from Indigenous homelands through the colonial powers to the United States.
The Community
How the town grew, who came, and what kind of place it became, traced through the census record.
Rivers & Rail
The rivers, canals and railroads that connected this place between 1830 and 1911.
Notable People
The people born, buried or genuinely tied to this exact place, with their stories.
Historical Maps
Historic maps of the location layered over how it looks today.
Finds & Access
Museum objects tied to the area, and the laws on searching, collecting and access here.
Literature
The old books, county histories and archives that mention this place, quoted with their sources.
Spotlight
A deep dive into the most remarkable, lesser-known history of the place, traced back to the record.
Points of Interest
The most significant historic sites and landmarks near the location, and why they matter.
Timeline
The whole story of the location told era by era, from first peoples to the present day.
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Frequently asked about San Diego

When does San Diego first appear in the US census?
San Diego, California first appears in the federal census in 1850, with a recorded population of 798.
What is the population of San Diego?
At the most recent federal census (2020), San Diego had a recorded population of 3,298,634.
Were any battles fought in San Diego?
18 documented military engagements took place in San Diego, including Kumeyaay Inter-Group Warfare – San Diego, Kumeyaay Attack on Mission San Diego 1769, Mission San Diego Revolt — 1775.
How many historic places are in San Diego?
161 sites are listed on the National Register of Historic Places in San Diego, California.
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