The Dakota Territory legislature created the county on April 14, 1885, with territory partitioned from Mercer County. It was named for Harry S. Oliver of Lisbon, North Dakota, a Republican politician and member of the Dakota Territory House of Representatives at the time. The county government was organized on May 18, with Sanger (then known as "Bentley") as county seat. The seat was moved to Center in 1902.[3][4]
The northeastern/eastern boundary of Oliver County is delineated by the Missouri River as it flows southeastward after leaving Lake Sakakawea. The county terrain consists of rolling hills, mostly devoted to agriculture.[5] The terrain slopes to the east, with the highest point a hill near its southwestern corner, at 2,382 ft (726 m) ASL.[6] The county has a total area of 731 square miles (1,890 km2), of which 723 square miles (1,870 km2) is land and 8.7 square miles (23 km2) (1.2%) is water.[7] It is the fifth-smallest county in North Dakota by area.
By sheer coincidence, the county seat, Center, named for being near the geographical center of the county, has also been calculated to be the geographic center of North America.[8]
U.S. Decennial Census[10] 1790-1960[11] 1900-1990[12] 1990-2000[13] 2010-2020[1]
2020 census
As of the census of 2020, there were 1,877 people.
2010 census
As of the census of 2010, there were 1,846 people, 756 households, and 554 families in the county. The population density was 2.55 people per square mile (0.98 people/km2). There were 905 housing units at an average density of 1.25 units per square mile (0.48/km2). The racial makeup of the county was 97.3% white, 1.5% American Indian, 0.2% black or African American, 0.2% Asian, 0.2% from other races, and 0.7% from two or more races. Those of Hispanic or Latino origin made up 1.0% of the population. In terms of ancestry, 66.8% were German, 19.3% were Norwegian, 7.6% were Russian, 6.3% were English, and 4.4% were American.
Of the 756 households, 25.0% had children under the age of 18 living with them, 65.5% were married couples living together, 4.8% had a female householder with no husband present, 26.7% were non-families, and 22.6% of all households were made up of individuals. The average household size was 2.44 and the average family size was 2.84. The median age was 47.6 years.
The median income for a household in the county was $62,308 and the median income for a family was $75,069. Males had a median income of $60,592 versus $28,409 for females. The per capita income for the county was $29,348. About 6.5% of families and 9.7% of the population were below the poverty line, including 13.0% of those under age 18 and 19.6% of those age 65 or over.
Oliver County voters are traditionally Republican. In only one national election since 1936 has the county selected the Democratic Party candidate (as of 2024).
United States presidential election results for Oliver County, North Dakota[14]
.jpg)
.svg){kind=small}
.svg){kind=small}
.svg){kind=small}
.svg){kind=small}
.svg){kind=small}
