ZIP Codes of Franklin County, WA

Population & People
Population & People
Total Population
98,034
Household Income
Household Income
Median Income
$92,332
Housing
Housing
Total Housing Units
30,943
Business & Economy
Business & Economy
Total Businesses
1,951
Employment
Employment
Employment Rate
62.08%
Education
Education
Bachelor's Degree+
20.96%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 6 ZIPs in this county.
Data Last Updated: July 1, 2026
ZIP Codes:6 ZIP Codes (4 Standard, 2 PO Box, 0 Unique) [See All]
Area Code:509
Timezone:Pacific (GMT -08:00)
Local Time:11:55:35 PM
Population:98,034 [See All]
FIPS:53021
CBSA:Kennewick-Richland, WA
Land Area:1,043 sq mi
Water Area:22 sq mi
Coordinates:46.5088, -118.9320
Quick Link:
https://www.zip-codes.com/county/wa-franklin.asp
Need Franklin data in your app? Look up ZIP, county, and city data with a single API call.
Try Free
Washington's #14 most populous county
98,034 residents across 6 ZIPs — #14 of 39 Washington counties.

Standout ZIPs in this County


Most Populous
Pasco · 87,044 people
88.8% of county total
Highest Income
Eltopia · $140,093 median
1.5× county average
Largest Land Area
Pasco · 537.7 sq mi
Spans the most ground
Fastest Growth
Pasco · 17.6% (10-yr)
74,025 → 87,044 residents
Most Educated
Pasco · 21.9% bachelor's+
11,156 of 50,827 adults 25+

Things worth knowing about Franklin County


98,034 residents live across 6 ZIPs covering 1,043 sq mi, served by 5 distinct USPS-recognized cities.

Population moved from 84,103 to 98,034 from 2014 to 2024 — a +16.6% change. 4 ZIPs gained residents, 1 lost.

The county's wealthiest ZIP 99330 (Eltopia, $140,093 median) and poorest ZIP 99343 (Mesa, $59,451) are 9.5 miles apart — a 2.4× income gap across local geography.

Median home values vary 2.2× across this county — from $253,000 in 99343 (Mesa) to $554,200 in 99330 (Eltopia).

Density varies 12× across the county — from 13 people/sq mi in 99330 (Eltopia) to 162 in 99301 (Pasco).

Educational attainment ranges from 11.4% bachelor's+ in 99326 (Connell) to 21.9% in 99301 (Pasco) — the breadth of educational profiles across the area.

Within Washington, this is the #14 most populous of 39 counties and ranks #9 for median household income with the #7 fastest decade growth .

Weighted by population, the typical household earns about $87,316 across the county — reflecting what a typical resident sees, not a simple ZIP average.

21.0% of adults age 25+ hold a bachelor's degree or higher (12,061 of 57,555 reporting).

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

Stories about Franklin 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
1,043
square miles
Avg density
94.0
people per sq mi
Population
98,034
across 6 ZIPs
Pasco
537.7 sq mi
87,044 residents
Mesa
199.9 sq mi
3,215 residents
Connell
194.6 sq mi
6,336 residents

Single-ZIP anchor

One ZIP holds the majority of this county's population — a sign of a county built around a single city or town.

Pasco

All ZIP Codes in Franklin County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
99301PascoStandard87,044$87,951537.717.6%
99326ConnellStandard6,336$82,500194.67.2%
99343MesaStandard3,215$59,451199.93.2%
99330EltopiaStandard1,210$140,09391.250.1%
99335KahlotusPO Box229$91,66719.3-6.5%
99302PascoPO Box0.0

Adjacent & Nearby Counties