ZIP Codes of Cowlitz County, WA

Population & People
Population & People
Total Population
117,032
Household Income
Household Income
Median Income
$81,700
Housing
Housing
Total Housing Units
48,050
Business & Economy
Business & Economy
Total Businesses
2,341
Employment
Employment
Employment Rate
53.10%
Education
Education
Bachelor's Degree+
17.49%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 11 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:11 ZIP Codes (11 Standard, 0 PO Box, 0 Unique) [See All]
Area Codes:360 / 564
Timezone:Pacific (GMT -08:00)
Local Time:2:14:15 PM
Population:117,032 [See All]
FIPS:53015
CBSA:Longview-Kelso, WA
Land Area:1,495 sq mi
Water Area:32 sq mi
Coordinates:46.1749, -122.6995
Quick Link:
https://www.zip-codes.com/county/wa-cowlitz.asp
Need Cowlitz data in your app? Look up ZIP, county, and city data with a single API call.
Try Free
Extreme geographic sprawl
The largest ZIP spans 3652× the smallest by area — 349.9 sq mi down to 0.10.

Standout ZIPs in this County


Most Populous
Longview · 50,635 people
43.3% of county total
Highest Income
Kalama · $116,435 median
1.4× county average
Largest Land Area
Toutle · 349.9 sq mi
Spans the most ground
Fastest Growth
Silverlake · 85.8% (10-yr)
1,193 → 2,216 residents
Most Educated
Silverlake · 37.5% bachelor's+
629 of 1,676 adults 25+

Things worth knowing about Cowlitz County


117,032 residents live across 11 ZIPs covering 1,495 sq mi, served by 11 distinct USPS-recognized cities.

Population moved from 104,574 to 117,032 from 2014 to 2024 — a +11.9% change. 8 ZIPs gained residents, 2 lost.

The county's wealthiest ZIP 98625 (Kalama, $116,435 median) and poorest ZIP 98632 (Longview, $66,305) are 23.2 miles apart — a 1.8× income gap across local geography.

Median home values vary 1.5× across this county — from $368,900 in 98626 (Kelso) to $538,000 in 98674 (Woodland).

Density varies 134× across the county — from 3 people/sq mi in 98649 (Toutle) to 355 in 98632 (Longview).

Educational attainment ranges from 14.6% bachelor's+ in 98649 (Toutle) to 37.5% in 98645 (Silverlake) — the breadth of educational profiles across the area.

Within Washington, this is the #12 most populous of 39 counties and ranks #19 for median household income with the #21 fastest decade growth .

Weighted by population, the typical household earns about $78,268 across the county — reflecting what a typical resident sees, not a simple ZIP average.

17.5% of adults age 25+ hold a bachelor's degree or higher (14,237 of 81,382 reporting).

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

Stories about Cowlitz County


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
1,495
square miles
Avg density
78.3
people per sq mi
Population
117,032
across 11 ZIPs
Toutle
349.9 sq mi
929 residents
Ariel
266.1 sq mi
1,267 residents
Kelso
187.1 sq mi
26,892 residents

All ZIP Codes in Cowlitz County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
98632LongviewStandard50,635$66,305142.64.1%
98626KelsoStandard26,892$75,528187.110.4%
98674WoodlandStandard17,525$94,24593.156.8%
98611Castle RockStandard9,302$86,322128.2-7.2%
98625KalamaStandard7,655$116,43583.816.2%
98645SilverlakeStandard2,216$101,42921.485.8%
98603ArielStandard1,267$78,281266.125.1%
98649ToutleStandard929$73,750349.9-21.4%
98581RyderwoodStandard419$43,00937.394.0%
98616CougarStandard192185.03.2%
98609CarrollsStandard00.1

Adjacent & Nearby Counties