San Luis Obispo County, California

San Luis Obispo County is a county in California, United States, on the Central Coast about 100
miles northwest of Santa Barbara. It had a population of 282,424 at the 2020 census, an estimated
281,555 by 2024, and covers 3,299 square miles (8,540 km2) of land centred near 35°23′N 120°27′W,
plus 317 square miles of coastal water inside its boundary.

San Luis Obispo is the county seat; its postal code is 93401. The county holds 7 cities and a
double-digit set of unincorporated communities, and it runs on Pacific Time. Its FIPS code is
06079.

Towns & Villages in San Luis Obispo County

San Luis Obispo County has 7 incorporated cities and 11 unincorporated communities large enough
to be tracked by the Census Bureau as a census designated place, or CDP. A number of smaller named
places — San Simeon, Harmony, Pozo, Whitley Gardens and several mobile-home parks around
Arroyo Grande and Nipomo — are locally known but too small for their own census count; they
are not listed below.

Two names on this list are easy to confuse. Shell Beach is not on the table above — it
was a separate seaside village until 1928, when it annexed into Pismo Beach, and it now functions
as a Pismo Beach neighborhood rather than a place of its own. Santa Margarita and California
Valley share the 93453 ZIP even though they sit roughly 30 miles apart on opposite sides of the
Salinas River valley.

ZIP Codes

• 93401 — San Luis Obispo (also serves 93403, 93405, 93407–93410 and 93412, all
  San Luis Obispo PO box or Cal Poly ZIPs)
• 93446 — Paso Robles
• 93422 — Atascadero
• 93420 — Arroyo Grande
• 93433 — Grover Beach
• 93442 — Morro Bay
• 93449 — Pismo Beach (Shell Beach mail is delivered under this code)
• 93444 — Nipomo
• 93402 — Los Osos
• 93465 — Templeton
• 93445 — Oceano
• 93428 — Cambria
• 93430 — Cayucos
• 93451 — San Miguel
• 93424 — Avila Beach
• 93461 — Shandon
• 93453 — Santa Margarita and California Valley

San Simeon and Harmony have no ZIP of their own; mail for both is routed through Cambria’s
93428 code.

Geography

San Luis Obispo County sits on California’s Central Coast, where the Santa Lucia Range runs
parallel to the shoreline and separates a narrow coastal strip from the inland Salinas River
valley. Of its roughly 3,616 square miles of total area, 3,299 are land and 317 are water —
the water figure is high for an inland-heavy county because the county’s legal boundary extends
several miles out into the Pacific Ocean along its 80-mile coastline. Morro Rock, a 581-foot
volcanic plug at the mouth of Morro Bay, is the county’s best-known landmark; Lake Nacimiento and
Lake San Antonio, both reservoirs on the Nacimiento and San Antonio rivers, are its largest bodies
of fresh water.

Monterey County and Kings County lie to the north and northeast, Kern County to the east, and
Santa Barbara County to the south; the Pacific Ocean forms the entire western boundary. Monterey County and Kern County both have live pages on this
site; Kings County’s page currently redirects to its New York namesake, and Santa Barbara County borders San
Luis Obispo directly to the south.

Demographics

San Luis Obispo County had a population of 282,424 at the 2020 census, and the latest estimate
puts the county near 281,555 residents, essentially flat over the past several years. San Luis
Obispo and Paso Robles are the two largest communities, together holding roughly a quarter of the
county’s population. Median household income runs close to $97,000, essentially in line with
California’s statewide median. Population density works out to about 86 people per square mile of
land, low for coastal California and a reflection of how much of the county is farmland, ranchland
and protected hillside rather than built-up town.

Economy & Local Life

Health care and social assistance employs the most workers in the county, about 16,554 people,
followed by retail trade at 14,209 and educational services at 14,030. California Polytechnic
State University, with roughly 22,000 students in the city of San Luis Obispo, is both the
county’s largest single institution and a major employer in its own right. Wine is the county’s
signature agricultural export — San Luis Obispo County is California’s third-largest wine
producer, behind only Sonoma and Napa, with vineyards concentrated around Paso Robles and the Edna
Valley south of the city of San Luis Obispo. The Diablo Canyon Power Plant, near Avila Beach, is
California’s last operating nuclear plant and one of the county’s largest single-site employers,
with its license extended to keep it running past its original 2025 retirement date. The county’s
biggest annual event is the California Mid-State Fair in Paso Robles each July, which draws crowds
well beyond the county’s own population for its concert lineup and livestock shows.

History

Franciscan missionary Junipero Serra founded Mission San Luis Obispo de Tolosa on 1 September
1772, naming it for Saint Louis of Toulouse, a 13th-century French bishop. The settlement that
grew up around the mission became the city of San Luis Obispo. California organized San Luis
Obispo County on 18 February 1850, one of the state’s original 27 counties at statehood, and named
it for the same mission.

Paso Robles grew around natural hot springs long used by the Salinan people before American
settlement; Atascadero was built from scratch in 1913 as a planned “colony” community, one of the
earliest such developments in the country. Diablo Canyon’s nuclear plant, approved in the 1960s
and completed in 1985 after prolonged seismic-safety review, remains the county’s most
consequential 20th-century development and its most persistent point of local debate.

Getting There

US Highway 101 runs the length of the county north to south through Paso Robles, Atascadero and
San Luis Obispo. State Route 1 follows the coast through Morro Bay, Cambria and San Simeon before
continuing north into Monterey County; State Route 46 connects Paso Robles east to Interstate 5,
and State Route 41 links Atascadero and Morro Bay toward Fresno. No interstate highway crosses the
county directly.

• Santa Barbara — about 100 miles south
• Bakersfield — about 110 miles east
• Fresno — about 130 miles northeast
• Salinas — about 100 miles north

San Luis Obispo County Regional Airport (SBP), on the south side of the city of San Luis
Obispo, offers commercial service to several West Coast hubs. Amtrak’s Pacific Surfliner and
Coast Starlight trains both stop at the San Luis Obispo station, with the Coast Starlight also
serving Paso Robles.

Frequently Asked Questions

Where is San Luis Obispo County located?
It sits on California’s Central Coast, about 100 miles northwest of Santa Barbara, bordered by
Monterey, Kings, Kern and Santa Barbara counties and the Pacific Ocean.

What is the population of San Luis Obispo County?
282,424 at the 2020 census, with a 2024 estimate near 281,555.

How big is San Luis Obispo County?
3,299 square miles of land (8,540 km2), plus 317 square miles of coastal water inside its
boundary.

What is the county seat of San Luis Obispo County?
San Luis Obispo, built around the 1772 mission of the same name, is the county seat.

How many towns and cities are in San Luis Obispo County?
Seven incorporated cities — San Luis Obispo, Paso Robles, Atascadero, Arroyo Grande, Grover
Beach, Morro Bay and Pismo Beach — plus 11 census-tracked unincorporated communities
including Nipomo, Los Osos and Cambria.

What ZIP codes does San Luis Obispo County use?
93401 for San Luis Obispo, 93446 for Paso Robles, 93422 for Atascadero, and separate codes for
each of the county’s smaller cities and CDPs — see the ZIP Codes section above.

What is San Luis Obispo County known for?
Its wine industry, California’s third-largest by production; California Polytechnic State
University; and the Diablo Canyon Power Plant, the state’s last operating nuclear facility.

More counties in this state: Towns
and villages in California.