California

San Luis Obispo

282,424
2020 population
1850
first census record
18
census records

About San Luis Obispo

San Luis Obispo, California, first appears in the United States federal census in 1850, when it recorded a population of 336. At the most recent census, in 2020, its population stood at 282,424.

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

On the ground today, one documented military engagement has been recorded within the county, among them Pecho Coast Violence – San Luis Obispo, and 37 places are listed on the National Register of Historic Places.

Population by decade

Census YearPopulationChart
2020282,424
2010269,637
2000246,681
1990217,162
1980155,435
1970105,690
196081,044
195051,417
194033,246
193029,613
192021,893
191019,383
190016,637
189016,072
18809,142
18704,772
18601,782
1850336
Source

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

Battles & engagements in San Luis Obispo

Military engagements that took place in San Luis Obispo, California.

Pecho Coast Violence – San Luis Obispo
1200

Historic places in San Luis Obispo

National Register of Historic Places listings in San Luis Obispo, California.

Mission San Miguel Arcangel
San Miguel
Carrizo Plain Rock Art Discontiguous District
California Valley
Piedras Blancas Light Station
San Simeon
Robles, Paso, Carnegie Library
Paso Robles
Old Santa Rosa Catholic Church and Cemetery
Cambria
Hearst San Simeon Estate
San Simeon
Rancho Canada de los Osos y Pecho y Islay
San Luis Obispo
San Luis Obispo Light Station
Avila Beach
Dana Adobe
Nipomo
Bank of Italy
Paso Robles
Pacific Coast Railway Company Grain Warehouse
San Luis Obispo
Angel, Myron, House
San Luis Obispo
Atascadero Printery
Atascadero
Pereira Octagon Barn
San Luis Obispo
Archeological Site 4 SLO 834
Atascadero
Price, John, House
Pismo Beach
Arroyo Grande IOOF Hall
Arroyo Grande
Jack, Robert, House
San Luis Obispo
Powerhouse, The
San Luis Obispo
San Luis Obispo Carnegie Library
San Luis Obispo
Administration Building, Atascadero Colony
Atascadero
Caledonia Adobe
San Miguel
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Everything a full report reveals about San Luis Obispo County, California

This page charts the census history of San Luis Obispo 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 Luis Obispo

When does San Luis Obispo first appear in the US census?
San Luis Obispo, California first appears in the federal census in 1850, with a recorded population of 336.
What is the population of San Luis Obispo?
At the most recent federal census (2020), San Luis Obispo had a recorded population of 282,424.
Were any battles fought in San Luis Obispo?
1 documented military engagement took place in San Luis Obispo, including Pecho Coast Violence – San Luis Obispo.
How many historic places are in San Luis Obispo?
37 sites are listed on the National Register of Historic Places in San Luis Obispo, California.
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