Oliver County is a county located in the U.S. state of North Dakota. As of the 2010 census, the population was 1,846, making it the fifth-least populous county in North Dakota. Its county seat and only city is Center.
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. The terrain slopes to the east, with the highest point a hill near its SW corner, at 2,382' ASL. The county has a total area of, of which is land and is water. It is the fifth-smallest county in North Dakota by area.
As of the 2000 United States Census, there were 2,065 people, 791 households, and 604 families in the county. The population density was 2.86/sqmi. There were 903 housing units at an average density of 1.25/sqmi. The racial makeup of the county was 97.58% White, 0.15% Black or African American, 1.26% Native American, 0.10% Asian, and 0.92% from two or more races. 0.63% of the population were Hispanic or Latino of any race. 59.2% were of German, 13.6% Norwegian and 6.5% American ancestry. There were 791 households out of which 35.50% had children under the age of 18 living with them, 69.20% were married couplesliving together, 3.90% had a female householder with no husband present, and 23.60% were non-families. 21.00% of all households were made up of individuals and 10.70% had someone living alone who was 65 years of age or older. The average household size was 2.61 and the average family size was 3.05. The county population contained 27.40% under the age of 18, 4.70% from 18 to 24, 23.50% from 25 to 44, 30.10% from 45 to 64, and 14.20% who were 65 years of age or older. The median age was 42 years. For every 100 females there were 107.50 males. For every 100 females age 18 and over, there were 106.20 males. The median income for a household in the county was $36,650, and the median income for a family was $45,430. Males had a median income of $40,577 versus $19,015 for females. The per capita income for the county was $16,271. About 11.20% of families and 14.90% of the population were below the poverty line, including 23.60% of those under age 18 and 13.90% of those age 65 or over.
2010 census
As of the 2010 United States Census, there were 1,846 people, 756 households, and 554 families in the county. The population density was 2.55/sqmi. There were 905 housing units at an average density of 1.25/sqmi. 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.
