Grant County, Washington

Grant County is a county in central Washington, United States, about 105 miles west of Spokane across the Columbia Basin. It had a population of 99,123 at the 2020 census, an estimated 105,727 by 2025, and covers 2,680 square miles (6,900 km2) of land centred near 47°13′N 119°28′W — the fourth-largest county in Washington by land area.

Ephrata is the county seat; its postal code is 98823. Moses Lake is the largest city. The county holds 10 cities, 5 incorporated towns, 11 census-designated places and about 10 smaller unincorporated communities, and it runs on Pacific Time. Its FIPS code is 53025.

Towns & Villages in Grant County

Grant County has 26 places with a 2020 census count: 15 incorporated cities and towns and 11 census-designated places. CDP stands for census designated place, a settled area the Census Bureau counts but which has no local government of its own. Washington has no civil townships, so places are listed county-wide.

Beyond these, the county has roughly 10 named unincorporated communities and rail sidings with no census count of their own: Adco, Adrian, Burke, Lakeview Park, Mae, Ruff, Smyrna, Stratford, Trinidad and Winchester.

A few entries need untangling. Krupp is officially a town named Krupp, but its post office and nearly everyone local call it Marlin — ZIP 98832 is registered under the Marlin name. The three Coulee communities are distinct places: Coulee City is a town on US 2 at the south end of Banks Lake, while Grand Coulee, Electric City and the town of Coulee Dam cluster 30 miles north around the dam itself. Coulee Dam’s 1,211 residents are a citywide figure — the town spreads across Grant, Douglas and Okanogan county lines. Moses Lake the city, Moses Lake North and Cascade Valley the CDPs, and Moses Lake the lake are four different things sharing one name.

ZIP Codes

• 98837 — Moses Lake (also serves the Cascade Valley, Moses Lake North and Wheeler CDPs)
• 98823 — Ephrata
• 98848 — Quincy
• 99349 — Mattawa (also serves Desert Aire)
• 98851 — Soap Lake
• 98857 — Warden
• 99357 — Royal City
• 99115 — Coulee City
• 99133 — Grand Coulee
• 99123 — Electric City
• 99321 — Beverly
• 99135 — Hartline
• 98832 — Marlin (the town of Krupp)
• 98824 — George (PO Box only)
• 98853 — Stratford (PO Box only)
• 98860 — Wilson Creek (PO Box only)

That is 16 ZIP codes in all: 13 standard-delivery and 3 PO Box-only. Most CDPs — Lakeview, Marine View, Crescent Bar, Banks Lake South, Schwana and Sunland Estates — have no ZIP of their own and take mail under the nearest post-office town’s code. Coulee Dam’s post office ZIP, 99116, is counted under the neighbouring counties rather than Grant County’s own codes.

Geography

Grant County occupies the heart of the Columbia Basin, a shrub-steppe plateau cut by coulees — dry canyons carved when Ice Age floods tore across the region. The largest, the Grand Coulee, runs down the county’s northern half and now holds Banks Lake, a 27-mile irrigation reservoir between Electric City and Coulee City. Dry Falls, a 3.5-mile-wide fossil waterfall at the head of the lower Grand Coulee, is one of the state’s best-known geologic sites. Of the county’s 2,791 square miles in total, 2,680 are land and 112 are water, about 4 percent — high for a dry region, thanks to Banks Lake, Moses Lake, Potholes Reservoir and the Columbia River, which forms most of the county’s western and northern boundary.

Douglas County lies to the north, Okanogan County to the northeast, Lincoln County and Adams County to the east, Franklin County to the southeast, Benton County to the south, Yakima County to the southwest and Kittitas County to the west, across the Columbia.

Demographics

Grant County counted 99,123 residents in 2020, and the latest estimate puts it near 105,727. Moses Lake is by far the largest community; with the adjoining Cascade Valley and Moses Lake North CDPs it holds about a third of the county’s population. Ephrata and Quincy come next. Median household income runs $73,267, well below Washington’s statewide figure of $98,141. Density works out to about 37 people per square mile of land, with most residents concentrated along the I-90 corridor and the irrigated farm belt south of it.

Economy & Local Life

Agriculture leads the county’s economy, employing about 8,892 workers — more than any other sector — ahead of health care and social assistance at 5,462 and manufacturing at 5,066. Columbia Basin Project irrigation turned this near-desert into one of the most productive farm counties in the United States; it regularly ranks first in the nation for potatoes and first in Washington for hay. Cheap hydropower is the county’s other engine: Grant County PUD runs the Priest Rapids and Wanapum dams on the Columbia, and low electricity rates drew a cluster of data centers to Quincy, including Microsoft’s, from 2007 onward. Moses Lake’s Grant County International Airport — a former Air Force base with a 13,500-foot runway — supports aviation testing, cargo and industrial tenants. The Gorge Amphitheatre outside George, a 25,000-capacity venue above the Columbia, hosts the county’s biggest crowds every summer, and the Grant County Fair runs in Moses Lake each August.

History

The Wanapum people have lived along the Columbia at Priest Rapids for centuries and never signed a removal treaty; a small Wanapum community remains near the river today. Homesteaders and the railroads brought wheat farming in the 1880s and 1890s, and the legislature created Grant County on 24 February 1909 from the eastern half of Douglas County, naming it for President Ulysses S. Grant.

Two federal projects then remade the county. Grand Coulee Dam, built 1933–1942 on the county’s northern border, became the largest hydroelectric producer in the United States and spawned the towns of Grand Coulee, Electric City and Coulee Dam. Its companion Columbia Basin Project began delivering irrigation water in 1952, converting hundreds of thousands of dry acres to row crops and drawing a new farm population. Larson Air Force Base operated at Moses Lake from 1942 to 1966; its runways survive as Grant County International Airport, where Boeing and Japan Airlines later based flight-training and test operations.

Getting There

Interstate 90 crosses the county’s southern half, with exits at George and Moses Lake. US 2 crosses the north through Coulee City, SR 28 links Quincy, Ephrata and Soap Lake, SR 17 runs north–south through Moses Lake and Soap Lake, SR 155 follows Banks Lake to Grand Coulee, and SR 243 tracks the Columbia past Mattawa and Desert Aire.

• Spokane — about 105 miles east of Moses Lake
• Seattle — about 180 miles west
• Wenatchee — about 35 miles northwest of Quincy
• Tri-Cities — about 70 miles south of Moses Lake

Grant County International Airport at Moses Lake handles general aviation, cargo and flight testing; the nearest scheduled passenger airports are Pangborn Memorial in East Wenatchee and Spokane International. Amtrak’s Empire Builder stops daily in each direction at the Ephrata station.

Frequently Asked Questions

Where is Grant County located?
In central Washington’s Columbia Basin, about 105 miles west of Spokane and 180 miles east of Seattle, bordered by Douglas, Okanogan, Lincoln, Adams, Franklin, Benton, Yakima and Kittitas counties.

What is the population of Grant County?
99,123 at the 2020 census, with a 2025 estimate near 105,727.

How big is Grant County?
2,791 square miles in total, of which 2,680 square miles are land — the fourth-largest land area of any Washington county.

What is the county seat of Grant County?
Ephrata, a city of 8,477 on SR 28, is the county seat; Moses Lake, three times its size, is the largest city.

How many towns and cities are in Grant County?
Fifteen incorporated places — 10 cities, led by Moses Lake, Ephrata and Quincy, and 5 towns — plus 11 census-designated places and about 10 unincorporated communities.

What ZIP codes does Grant County use?
Sixteen: 98837 for Moses Lake, 98823 for Ephrata, 98848 for Quincy, 99349 for Mattawa and Desert Aire, plus 98824, 98832, 98851, 98853, 98857, 98860, 99115, 99123, 99133, 99135, 99321 and 99357.

What is Grant County known for?
Grand Coulee Dam, the largest hydroelectric plant in the United States; the nation’s top potato-growing farmland; and the Gorge Amphitheatre concert venue at George.

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