|Williams County, North Dakota|
Location within the U.S. state of North Dakota
North Dakota's location within the U.S.
|• Total||2,148 sq mi (5,563 km2)|
|• Land||2,077 sq mi (5,379 km2)|
|• Water||70 sq mi (181 km2), 3.3%|
|• ( 2017)||33,349|
|• Density||16.06/sq mi (6.20/km2)|
|Time zone||Central: UTC−6/ −5|
Williams County is a county in the U.S. state of North Dakota. As of the 2010 United States Census, the population was 22,398.  Its county seat is Williston.  Between 2010 and 2017, according to Census Bureau estimates, it was the second fastest growing county in the United States, trailing only neighboring McKenzie County, to its south.
The Williston Micropolitan Statistical Area includes all of Williams County. The Micropolitan Statistical Area is the fastest-growing Primary Statistical Area, growing 48.9% in population from 2010 to 2017.
In 2014, Williams County had the lowest percentage of unemployed people of any county in the United States, at 1.2 percent. 
There have been two Williams counties in the history of North Dakota. The first, created in 1873, was located south of the Missouri River near where Dunn and Mercer counties are today. This county continued to exist through North Dakota statehood, and even while the second Williams County was created in 1891. The first Williams County was extinguished by a county referendum on 8 November 1892; part of its territory was absorbed by Mercer County and the rest reverted to unorganized territory.
The second Williams County was created by the North Dakota legislature on 2 March 1891, from the previous counties of Buford and Flannery, which were dissolved. The government of this county was organized on 8 December 1891. This county's boundaries were altered in 1910, when a portion of its territory was annexed to create Divide County. Its boundaries have remained unchanged since then. 
The county is named for Erastus Appleman Williams, who served in the Dakota Territory legislature and the North Dakota legislature. 
Williams County lies on the west edge of North Dakota. Its west boundary line abuts the east boundary line of the state of Montana. The Missouri River flows eastward along the county's south boundary line. Horse Creek and Willow Creek flow to the west across the upper portion of the county. The terrain consists of isolated hills amid rolling hilly semi-arid stretches. The area is partly devoted to agriculture.  The terrain is highest across its midpoint, and slopes to the NW and SE. Its highest point is a hill near the NE corner, at 2,470' (753m) ASL.  The county has a total area of 2,148 square miles (5,560 km2), of which 2,077 square miles (5,380 km2) is land and 70 square miles (180 km2) (3.3%) is water.  It is the fourth-largest county in North Dakota by area.
Lake Sakakawea, a reservoir on the Missouri River, is situated on the southern boundary of the county. Little Muddy Creek is entirely within Williams County. The confluence of the Yellowstone River with the Missouri is west of Williston.
The Fort Union Trading Post National Historic Site is located in Williams County along the Missouri River on the Montana border.
Protected areas 
- Alkali Lake
- Blacktail Lake
- Cottonwood Lake
- Epping Dam
- Green Lake
- Helle Slough
- Holm Lake
- Lake Trenton
- Lake Zahl
- McLeod Lake
- Shirley Lake
- Tioga River Dam
- Twin Lakes
|US Decennial Census
1790-1960  1900-1990 
1990-2000  2010-2017 
As of the 2000 United States Census, there were 19,761 people, 8,095 households, and 5,261 families in the county. The population density was 10 people per square mile (4/km²). There were 9,680 housing units at an average density of 5 per square mile (2/km²). The racial makeup of the county was 92.95% White, 0.12% Black or African American, 4.40% Native American, 0.18% Asian, 0.01% Pacific Islander, 0.14% from other races, and 2.21% from two or more races. 0.94% of the population were Hispanic or Latino of any race. 48.3% were of Norwegian and 22.0% German ancestry.
There were 8,095 households out of which 31.2% had children under the age of 18 living with them, 53.3% were married couples living together, 8.8% had a female householder with no husband present, and 35.0% were non-families. Of all households 30.9% were made up of individuals and 13.1% had someone living alone who was 65 years of age or older. The average household size was 2.38 and the average family size was 2.99.
The county population contained 26.2% under the age of 18, 7.80% from 18 to 24, 25.5% from 25 to 44, 24.0% from 45 to 64, and 16.5% who were 65 years of age or older. The median age was 40 years. For every 100 females there were 96.2 males. For every 100 females age 18 and over, there were 93.6 males.
The median income for a household in the county was $31,491, and the median income for a family was $39,065. Males had a median income of $29,884 versus $19,329 for females. The per capita income for the county was $16,763. About 9.6% of families and 11.9% of the population were below the poverty line, including 16.5% of those under age 18 and 8.1% of those age 65 or over.
As of the 2010 census, there were 22,398 people, 9,293 households, and 5,746 families in the county.  The population density was 10.8 inhabitants per square mile (4.2/km2). There were 10,464 housing units at an average density of 5.0 per square mile (1.9/km2).  The racial makeup of the county was 92.1% white, 4.0% American Indian, 0.4% Asian, 0.3% black or African American, 0.3% from other races, and 2.9% from two or more races. Those of Hispanic or Latino origin made up 1.9% of the population.  In terms of ancestry, 46.2% were of Norwegian, 35.9% of German, 9.8% of Irish, 4.5% of Swedish and 4.4% of English ancestry. 
Of the 9,293 households, 28.5% had children under the age of 18 living with them, 49.8% were married couples living together, 7.7% had a female householder with no husband present, 38.2% were non-families, and 31.5% of all households were made up of individuals. The average household size was 2.35 and the average family size was 2.95. The median age was 39.0 years. 
The median income for a household in the county was $55,396 and the median income for a family was $67,875. Males had a median income of $50,735 versus $27,071 for females. The per capita income for the county was $29,153. About 4.7% of families and 8.7% of the population were below the poverty line, including 9.7% of those under age 18 and 10.4% of those age 65 or over. 
- The Williston Herald
- Barr Butte
- Big Meadow
- Big Stone
- Blue Ridge
- Bull Butte
- Cow Creek
- Dry Fork
- East Fork
- Golden Valley
- Good Luck
- Missouri Ridge
- New Home
- Pleasant Valley
- Rock Island
- Round Prairie
- Sauk Valley
- South Meadow
- Stony Creek
- Twelve Mile
- West Bank
- Hofflund 
Williams County voters have been reliably Republican for decades. In no national election since 1964 has the county selected the Democratic Party candidate.
- "State & County QuickFacts". United States Census Bureau. Retrieved November 1, 2013.
- "Find a County". National Association of Counties. Retrieved June 7, 2011.
- "Labor Force Data by County, 2014 Annual Averages". US Bureau of Labor Statistics. Retrieved 31 July 2015.
- "Dakota Territory, South Dakota, and North Dakota: Individual County Chronologies". Dakota Territory Atlas of Historical County Boundaries. The Newberry Library. 2006. Retrieved February 3, 2015.
- "County History". Official Portal for North Dakota State Government. Retrieved May 4, 2011.
- Williams County ND Google Maps (accessed 19 February 2019)
- "Find an Altitude/Williams County ND" Google Maps (accessed 19 February 2019)
- "2010 Census Gazetteer Files". US Census Bureau. August 22, 2012. Archived from the original on January 29, 2015. Retrieved February 1, 2015.
- "Population and Housing Unit Estimates". Retrieved 19 February 2019.
- "US Decennial Census". US Census Bureau. Retrieved February 1, 2015.
- "Historical Census Browser". University of Virginia Library. Retrieved February 1, 2015.
- Forstall, Richard L., ed. (April 20, 1995). "Population of Counties by Decennial Census: 1900 to 1990". US Census Bureau. Retrieved February 1, 2015.
- "Census 2000 PHC-T-4. Ranking Tables for Counties: 1990 and 2000" (PDF). US Census Bureau. April 2, 2001. Retrieved February 1, 2015.
- "Profile of General Population and Housing Characteristics: 2010 Demographic Profile Data". US Census Bureau. Retrieved April 3, 2016.
- "Population, Housing Units, Area, and Density: 2010 - County". US Census Bureau. Retrieved April 3, 2016.
- "Selected Social Characteristics in the US – 2006-2010 American Community Survey 5-Year Estimates". US Census Bureau. Retrieved April 3, 2016.
- "Selected Economic Characteristics – 2006-2010 American Community Survey 5-Year Estimates". US Census Bureau. Retrieved April 3, 2016.
- US Census Bureau: Boundary Changes
- Leip, David. "Atlas of US Presidential Elections". uselectionatlas.org. Retrieved 13 April 2018.
- The leading "other" candidate, Socialist Eugene Debs received 588 votes, while Progressive Theodore Roosevelt, received 402 votes, Prohibition candidate Eugene Chafin received 45 votes.