Williams County, North Dakota

Williams County
The Williams County Courthouse in Williston.
Location within the U.S. state of North Dakota
North Dakota's location within the U.S.
Coordinates: 48°21′21″N 103°30′05″W / 48.355765°N 103.501333°W / 48.355765; -103.501333
Country United States
State North Dakota
FoundedMarch 2, 1891 (created)
December 8, 1891 (organized)
Named afterErastus Appleman Williams
SeatWilliston
Largest cityWilliston
Area
  Total
2,147.808 sq mi (5,562.80 km2)
  Land2,077.600 sq mi (5,380.96 km2)
  Water70.208 sq mi (181.84 km2)  3.27%
Population
 (2020)
  Total
40,950
  Estimate 
(2024)
40,763
  Density19.619/sq mi (7.575/km2)
Time zoneUTC−6 (Central)
  Summer (DST)UTC−5 (CDT)
Area code701
Congressional districtAt-large
Websitewilliamsnd.com

Williams County is located on the western border of the U.S. state of North Dakota, next to Montana. As of the 2020 census, the population was 40,950, and was estimated to be 40,763 in 2024, making it the fifth-most populous county in North Dakota. The county seat and the largest city is Williston.

The Williston Micropolitan Statistical Area includes all of Williams County. It is bordered on the south by the upper Missouri River, whose confluence with its tributary Yellowstone River is located just east of the border with Montana.