Franklin County is a county in Washington, United States, about 140 miles southwest of Spokane. It had a population of 96,749 at the 2020 census, an estimated 102,612 by 2025, and covers 1,264.96 square miles (3,276.23 km2) centred near 46°32′N 118°54′W.
Pasco is the county seat and the county’s only city over 5,000 residents; its postal code is 99301. The county holds 4 incorporated cities, 2 census-designated places and 3 unincorporated communities with no formal government, and it runs on Pacific Time. Its FIPS code is 53021.
Towns & Villages in Franklin County
Franklin County has 9 named places on record: 4 incorporated cities and 5 unincorporated places, split between census-designated places (CDPs, mapped by the Census Bureau but with no local government) and smaller unincorporated communities.
| Place | Type | Pop. | ZIP |
|---|---|---|---|
| Pasco | City · seat | 77,108 | 99301, 99302 |
| Connell | City | 5,441 | 99326 |
| West Pasco | CDP | 1,747 | 99301 |
| Basin City | CDP | 1,063 | 99343 |
| Mesa | City | 385 | 99343 |
| Kahlotus | City | 147 | 99335 |
| Eltopia | Unincorp. | — | — |
| Farrington | Unincorp. | — | — |
| Harder | Unincorp. | — | — |
West Pasco is a census-designated place carved out of Pasco’s western edge; it is not a separate municipality and its residents are governed by the city of Pasco next door. Basin City and Mesa sit close together on the county’s western plain and are sometimes confused — Basin City is the larger of the two and lies inside the Columbia Basin Irrigation Project, while Mesa is an incorporated city three miles to its northwest.
ZIP Codes
- 99301 — Pasco (also covers West Pasco)
- 99302 — Pasco (a post office box ZIP)
- 99326 — Connell
- 99335 — Kahlotus
- 99343 — Mesa and Basin City
Eltopia, Farrington and Harder have no ZIP code of their own; mail to those communities is delivered under Pasco’s or Connell’s code depending on location.
Geography
Franklin County lies on the Columbia Plateau in south-central Washington, a flat-to-rolling landscape of basalt bedrock and wind-deposited soil. Of its 1,264.96 square miles, 1,241.60 are land and 23.36 are water, about 1.8 percent. The Columbia River forms the county’s entire western and southern boundary, and the Snake River meets the Columbia at Sacajawea State Park near Pasco. The Ice Age Floods carved the coulees that cross the county’s northwest corner, including the channel that holds Kahlotus and the dry falls near Washtucna.
Adams County lies to the north, Whitman County to the east, Walla Walla and Columbia counties to the southeast, Benton County to the southwest across the Columbia River, and Grant County to the northwest. Adams County, Whitman County, Walla Walla County, Columbia County, Benton County and Grant County all border Franklin.
Demographics
Franklin County had a population of 96,749 at the 2020 census, and the latest estimate puts the county near 102,612 residents. Pasco is by far the largest community, holding about four-fifths of the county’s population, with Connell a distant second. The county’s median household income is $81,604, below Washington’s statewide figure of $94,605 (2023 ACS). As of 2020 the county was 54.2 percent Hispanic or Latino, with a median age of 30.9 years, both notably younger and more Hispanic than Washington as a whole. Population density works out to roughly 78 people per square mile of land, low even by rural Washington standards outside the Tri-Cities core.
Economy & Local Life
Agriculture and food processing anchor the county’s economy, built on Columbia Basin Project irrigation water that turned the desert plain into potato, wine-grape and row-crop country. Lamb Weston runs a major potato-processing plant in the county, and Tyson Fresh Meats operates a large beef-processing plant in Pasco, among the region’s biggest private employers. BNSF Railway maintains a rail yard in Pasco, a legacy of the Northern Pacific line that first brought settlement to the area. Connell’s economy also rests partly on Coyote Ridge Corrections Center, a state prison capable of holding roughly 2,600 offenders, one of the town’s largest employers. Pasco is part of the Tri-Cities metropolitan area with Kennewick and Richland in neighboring Benton County. The county’s biggest annual event is Pasco’s Fiery Foods Festival each September, alongside the long-running Pasco Farmers Market that runs May through October.
History
The Washington Territorial Legislature created Franklin County on November 28, 1883, out of Whitman County, naming it for Benjamin Franklin. Ainsworth, a rough railroad town at the Snake-Columbia confluence, served as the first county seat. After the Northern Pacific finished its Snake River bridge in 1884, businesses and buildings moved to the new townsite of Pasco, and by 1885 the legislature had shifted the county seat there. Ainsworth was later absorbed into Pasco’s growth and no longer exists as a separate place.
The Columbia Basin Project, built starting in the 1930s and expanded after World War II, brought irrigation canals across the county’s western half and converted sagebrush rangeland into some of the state’s most productive farmland, drawing the agricultural workforce that shapes the county today.
Getting There
U.S. Route 395 runs the length of the county through Pasco and Connell, connecting to Interstate 90 at Ritzville to the north and Interstate 82 at the Tri-Cities to the south. Interstate 182 links Pasco to Kennewick and Richland. State Route 260 also serves Connell and the county’s eastern reaches.
- Kennewick — about 10 miles southwest
- Walla Walla — about 45 miles southeast
- Ritzville — about 45 miles north
- Spokane — about 140 miles northeast
Tri-Cities Airport, on Pasco’s north side, is the county’s own commercial airport with daily flights to Seattle, Denver, Salt Lake City and other hubs. Amtrak’s Empire Builder stops at the Pasco station downtown, connecting to Spokane and Seattle.
Frequently Asked Questions
Where is Franklin County located?
It sits on the Columbia Plateau in south-central Washington, about 140 miles southwest of Spokane, bordered by Adams, Whitman, Walla Walla, Columbia, Benton and Grant counties.
What is the population of Franklin County?
96,749 at the 2020 census, with a 2025 estimate near 102,612.
How big is Franklin County?
1,264.96 square miles (3,276.23 km2), of which 1,241.60 square miles are land.
What is the county seat of Franklin County?
Pasco is the county seat. Its postal code is 99301.
How many towns and cities are in Franklin County?
Four incorporated cities — Pasco, Connell, Mesa and Kahlotus — plus the census-designated places West Pasco and Basin City, and the unincorporated communities Eltopia, Farrington and Harder.
What ZIP codes does Franklin County use?
99301 and 99302 for Pasco and West Pasco; 99326 for Connell; 99335 for Kahlotus; and 99343 for Mesa and Basin City.
What is Franklin County known for?
Irrigated potato and wine-grape farming under the Columbia Basin Project, the Tri-Cities metro area anchored by Pasco, and Coyote Ridge Corrections Center in Connell.
More counties in this state: Towns and villages in Washington.