ZIP Codes of Colusa County, CA

Population & People
Population & People
Total Population
22,045
Household Income
Household Income
Median Income
$68,462
Housing
Housing
Total Housing Units
8,224
Business & Economy
Business & Economy
Total Businesses
415
Employment
Employment
Employment Rate
56.98%
Education
Education
Bachelor's Degree+
16.33%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 7 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:7 ZIP Codes (5 Standard, 2 PO Box, 0 Unique) [See All]
Area Code:530
Timezone:Pacific (GMT -08:00)
Local Time:2:11:28 PM
Population:22,045 [See All]
FIPS:06011
Land Area:1,148 sq mi
Water Area:6 sq mi
Coordinates:39.1998, -122.1540
Quick Link:
https://www.zip-codes.com/county/ca-colusa.asp
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Notable income spread
Median income ranges $24,766 to $95,122 across ZIPs — a 3.8× gap.

Standout ZIPs in this County


Most Populous
Colusa · 7,701 people
34.9% of county total
Highest Income
Williams · $95,122 median
1.4× county average
Largest Land Area
Stonyford · 354.1 sq mi
Spans the most ground
Fastest Growth
Williams · 13.5% (10-yr)
5,979 → 6,786 residents
Most Educated
Arbuckle · 17.6% bachelor's+
548 of 3,113 adults 25+

Things worth knowing about Colusa County


22,045 residents live across 7 ZIPs covering 1,148 sq mi, served by 7 distinct USPS-recognized cities.

Population moved from 21,612 to 22,045 from 2014 to 2024 — a +2.0% change. 3 ZIPs gained residents, 4 lost.

The county's wealthiest ZIP 95987 (Williams, $95,122 median) and poorest ZIP 95979 (Stonyford, $24,766) are 18.3 miles apart — a 3.8× income gap across local geography.

Median home values vary 2.4× across this county — from $184,400 in 95979 (Stonyford) to $435,800 in 95912 (Arbuckle).

Density varies 8355× across the county — from 2 people/sq mi in 95979 (Stonyford) to 13,165 in 95950 (Grimes).

Educational attainment ranges from 5.6% bachelor's+ in 95950 (Grimes) to 19.2% in 95979 (Stonyford) — the breadth of educational profiles across the area.

Within California, this is the #50 most populous of 58 counties and ranks #46 for median household income .

Weighted by population, the typical household earns about $79,891 across the county — reflecting what a typical resident sees, not a simple ZIP average.

16.3% of adults age 25+ hold a bachelor's degree or higher (2,307 of 14,129 reporting).

5 Standard delivery, 2 PO Box only, 0 single-entity Unique ZIPs serve this county.

Stories about Colusa County


Two counties in one

Median household income spans 3.8× between the wealthiest and poorest ZIPs — a sign of significant intra-county inequality.

Wealthiest ZIP
Williams
Median income: $95,122
Population: 6,786
Bachelor's+: 14.5%
vs
Poorest ZIP (pop >= 500)
Stonyford
Median income: $24,766
Population: 558
Bachelor's+: 19.2%
For every $1 of household income in 95979, the typical household in 95987 earns $3.84.

Big & sparse

A frontier county — vast land area with only a few residents per square mile. Daily life looks very different here than in the country's denser counties.

Total area
1,148
square miles
Avg density
19.2
people per sq mi
Population
22,045
across 7 ZIPs
Stonyford
354.1 sq mi
558 residents
Williams
288.1 sq mi
6,786 residents
Arbuckle
268.1 sq mi
4,855 residents

All ZIP Codes in Colusa County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
95932ColusaStandard7,701$66,964143.3-1.4%
95987WilliamsStandard6,786$95,122288.113.5%
95912ArbuckleStandard4,855$86,457268.16.7%
95955MaxwellPO Box1,40569.51.5%
95979StonyfordStandard558$24,766354.1-18.5%
95970PrincetonStandard453$69,00025.2-6.0%
95950GrimesPO Box2870.0-60.4%

Adjacent & Nearby Counties