The county was formed in 1862, and was organized in 1874.
Geography
Big Stone County lies on the west side of Minnesota. Its southwest boundary line abuts the east boundary line of the state of South Dakota. The Little Minnesota River flows along the county's SW boundary. Since 1937 a dam has impounded the river's waters, creating Big Stone Lake. Water flowing out from this lake flows along the south boundary line of the county, and is known as the Minnesota River from that point. Fish Creek flows southwesterly through the NW part of the county, discharging into Big Stone Lake at the county's SW boundary. The terrain of Big Stone County is low rolling hills, wooded or devoted to agriculture. The terrain generally slopes to the south and east, although its southwestern portion slopes to the river valley. Its highest point is on its north line near the NW corner, 2.9 miles east of Lagoona Beach, at 1,201' ASL. The county has a total area of, of which is land and is water.
In recent years, average temperatures in the county seat of Ortonville have ranged from a low of in January to a high of in July, although a record low of was recorded in February 1994 and a record high of was recorded in July 1966. Average monthly precipitation ranged from in December to in July.
Demographics
2000 Census
As of the 2000 United States Census, there were 5,820 people, 2,377 households, and 1,611 families in the county. The population density was 11.7/sqmi. There were 3,171 housing units at an average density of 6.35/sqmi. The racial makeup of the county was 98.44% White, 0.17% Black or African American, 0.52% Native American, 0.41% Asian, 0.12% from other races, and 0.34% from two or more races. 0.34% of the population were Hispanic or Latino of any race. 45.7% were of German, 21.0% Norwegian, 8.0% Swedish and 6.3% Irish ancestry. There were 2,377 households out of which 29.00% had children under the age of 18 living with them, 59.60% were married couples living together, 5.30% had a female householder with no husband present, and 32.20% were non-families. 30.20% of all households were made up of individuals and 16.90% 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 2.97. The county population contained 24.80% under the age of 18, 5.30% from 18 to 24, 21.90% from 25 to 44, 24.00% from 45 to 64, and 24.00% who were 65 years of age or older. The median age was 44 years. For every 100 females there were 94.30 males. For every 100 females age 18 and over, there were 91.10 males. The median income for a household in the county was $30,721, and the median income for a family was $37,354. Males had a median income of $27,857 versus $20,123 for females. The per capita income for the county was $15,708. About 7.80% of families and 12.00% of the population were below the poverty line, including 14.50% of those under age 18 and 8.80% of those age 65 or over.
