Placer County, California

Placer County is a county in California, United States, about 30 miles northeast of
Sacramento. It had a population of 404,739 at the 2020 census, an estimated 442,081 by 2025, and
covers 1,407 square miles (3,640 km2) of land centred near 39°04′N 120°44′W.

Auburn is the county seat; its postal code is 95602. The county holds 6 incorporated cities, 17
census-designated places and a further group of small unincorporated communities across no civil
townships — California abolished the township as a governing unit, so places here fall
directly under county jurisdiction. Placer runs on Pacific Time. Its FIPS code is 06061.

Towns & Villages in Placer County

Placer County has 6 incorporated cities, all with their own city government. Roseville and
Rocklin, in the county’s flat southwest corner, are by far the largest; Colfax, up in the
foothills, is the smallest.

Beyond the six cities, the Census Bureau tracks 17 census-designated places (CDPs) —
populated areas with no city government of their own. The largest, Granite Bay, sits between
Roseville and Folsom Lake and is bigger than four of the county’s incorporated cities.

Beyond those 23 places, maps of Placer County carry several dozen more unincorporated place
names with no census population of their own, mostly old mining camps and rail sidings along the
Interstate 80 and Highway 20 corridors — Applegate, Baxter, Blue Canyon, Bowman, Brockway,
Emigrant Gap, Iowa Hill, Northstar, Ophir, Olympic Valley and Weimar among them. Olympic Valley,
formerly Squaw Valley, hosted the 1960 Winter Olympics; it has no population count of its own
because the Census Bureau folds it into a larger tract. The county’s old scrape list also
carried duplicate and unverifiable entries — a second “Cedar Flat”, an “Andover”
and a “Golden Chain MH Park” among them — that traced to no Census place or gazetteer
record and are dropped here rather than repeated on faith.

ZIP Codes

• 95602–95604 — Auburn
• 95661, 95678, 95747 — Roseville
• 95677, 95765 — Rocklin
• 95648 — Lincoln (also covers Sheridan)
• 95650 — Loomis (also covers Penryn)
• 95713 — Colfax (also covers Alta and Dutch Flat)
• 95746 — Granite Bay
• 95603 — North Auburn
• 96143 — Kings Beach, Carnelian Bay and Tahoe Vista
• 95722 — Meadow Vista
• 95631 — Foresthill
• 95724 — Soda Springs, serving the Kingvale area near Donner Summit

Newcastle uses Auburn’s and Rocklin’s ZIPs depending on the street; Tahoma and
Sunnyside-Tahoe City share the North Lake Tahoe 96145/96148 range centred on Tahoe City in
neighbouring Placer-El Dorado border country. Cedar Flat has no ZIP of its own.

Geography

Placer County climbs from the flat Sacramento Valley floor in the southwest, through the
Sierra Nevada foothills around Auburn and Colfax, to the Sierra crest and the north shore of Lake
Tahoe in the east. Of its total area, 1,407 square miles are land and about 95 square miles are
water — a share driven almost entirely by Lake Tahoe, of which roughly 40 percent by surface
area lies inside the county. The North Fork American River cuts the Auburn area’s deep canyon,
and the Bear River and Yuba River trace parts of the county’s northern boundary.

Nevada County lies to the north, Sutter and Yuba counties to the northwest, Sacramento County
to the southwest, El Dorado County to the south, and Nevada’s Washoe County, across Lake
Tahoe and the Sierra crest, to the east. Nevada County,
Sutter County,
Yuba County,
Sacramento County and
El Dorado County all border Placer
directly.

Demographics

Placer County had a population of 404,739 at the 2020 census, and a 2024 estimate put the
county near 419,156 residents. Roseville and Rocklin together hold more than half the county’s
population. Median household income runs about $115,998, well above California’s statewide
figure of $95,521 (2023 ACS), reflecting the county’s Sacramento-suburb and Sierra-resort
economy. Population density works out to roughly 288 people per square mile of land, concentrated
almost entirely in the southwestern cities; the Sierra half of the county is sparsely settled.

Economy & Local Life

Health care and social assistance is the county’s largest employment sector, with about
30,284 workers, ahead of retail trade at 20,060 and professional, scientific and technical
services at 19,706. Kaiser Permanente runs major medical facilities in Roseville and is among the
county’s largest single employers, alongside Placer County government itself and Union Pacific
Railroad, which maintains a rail yard and roundhouse in Roseville. Sierra College, based in
Rocklin, is the county’s largest community college and a major local employer in its own right.
The county’s biggest annual event is the Auburn-based California International Marathon, run
each December from Folsom to the state Capitol in Sacramento, which draws thousands of runners
through the region.

History

California’s legislature formed Placer County on 25 April 1851, taking territory from
Sutter and Yuba counties. Its name comes from the Spanish word placer, meaning a surface mineral
deposit — a direct reference to the gold placer deposits worked across the county during the
Gold Rush. Auburn was named the county seat that same year and has held the title ever since.

The discovery of gold in the Sierra foothills in 1848 drew tens of thousands of miners into
what became Placer County within three years, and mining camps at Auburn, Iowa Hill, Michigan
Bluff, Dutch Flat and Todd Valley grew up along the ridges above the American and Bear rivers.
The Central Pacific Railroad, built through Colfax and over Donner Summit in the 1860s, opened the
eastern part of the county to timber and later tourism. In 1960, Squaw Valley — renamed
Olympic Valley in 2021 — hosted the VIII Winter Olympic Games, the only Winter Games held in
California.

Getting There

Interstate 80 runs the length of the county from Roseville and Rocklin through Auburn and
Colfax to Donner Summit and the Nevada line. State Route 65 serves Lincoln and Roseville, and
State Route 49, the Gold Country highway, runs south from Auburn toward El Dorado County.

• Sacramento — about 30 miles southwest
• Reno, Nevada — about 90 miles northeast
• South Lake Tahoe — about 40 miles southeast
• Grass Valley — about 20 miles north

Sacramento International Airport, about 35 miles southwest of Auburn, is the nearest major
commercial airport. Auburn Municipal Airport handles general aviation. Amtrak’s California
Zephyr stops at the Colfax and Roseville stations on its run between the Bay Area and Chicago via
Donner Pass.

Frequently Asked Questions

Where is Placer County located?
It sits in north-central California, stretching from the Sacramento Valley suburbs of Roseville
and Rocklin east across the Sierra Nevada to the north shore of Lake Tahoe.

What is the population of Placer County?
404,739 at the 2020 census, with a 2025 estimate near 442,081.

How big is Placer County?
1,407 square miles (3,640 km2) of land, plus about 95 square miles of water, most of it Lake
Tahoe.

What is the county seat of Placer County?
Auburn is the county seat and has held that role since the county was formed in 1851.

How many towns and cities are in Placer County?
Six incorporated cities — Roseville, Rocklin, Lincoln, Auburn, Loomis and Colfax —
plus 17 census-designated places including Granite Bay, North Auburn and Kings Beach.

What ZIP codes does Placer County use?
95602 through 95604 for Auburn, 95661/95678/95747 for Roseville, 95677/95765 for Rocklin, 95648
for Lincoln, 95650 for Loomis, 95713 for Colfax, and 96143 for the Kings Beach–Tahoe Vista
area on Lake Tahoe’s north shore.

What is Placer County known for?
Gold Rush history around Auburn and Dutch Flat, its share of Lake Tahoe’s north shore, and
hosting the 1960 Winter Olympics at what is now Olympic Valley.

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