Bon Homme County was created in 1862. "Bon Homme" was first used by Lewis and Clark in 1804 as the name for a 2,000 acre island in the Missouri River. When settlers arrived in the late 1850s they borrowed the name, and when the county was created it was named for the village of Bon Homme. A proposal to change the county name to "Jefferson" in 1865 was rejected. The French word "bonhomme" means "good man."[4][5] The original island is now submerged under Lewis and Clark Lake.[6] The village of Bon Homme was the original county seat until 1885, when it moved to Tyndall.[7]
Bon Homme County is the point of origin for the Siberian alien, Kali tragus, a type of tumbleweed, first reported here in 1877, probably introduced in a shipment of flax seed from Ukraine.[8]
Bon Homme County lies on the south line of South Dakota. Its south boundary line abuts the north boundary line of the state of Nebraska (across the Missouri River). The west boundary line of the county is roughly defined by Choteau Creek, which flows southward to discharge in the river. The county terrain consists of low rolling hills, sloping to the river valley; most of the area is devoted to agriculture. The terrain's highest point is the county's NW corner, at 1,883 ft (574 m) ASL.[9]
The county has a total area of 582 square miles (1,510 km2), of which 564 square miles (1,460 km2) is land and 18 square miles (47 km2) (3.1%) is water.[10]
U.S. Decennial Census[21] 1790-1960[22] 1900-1990[23] 1990-2000[24] 2010-2020[2]
2020 census
As of the 2020 census, there were 7,003 people, 2,378 households, and 1,503 families residing in the county.[25] The population density was 12.4 inhabitants per square mile (4.8/km2). There were 2,810 housing units.
2010 census
As of the 2010 census, there were 7,070 people, 2,457 households, and 1,572 families in the county. The population density was 12.5 inhabitants per square mile (4.8/km2). There were 2,931 housing units at an average density of 5.2 per square mile (2.0/km2). The racial makeup of the county was 89.8% white, 7.1% American Indian, 1.0% black or African American, 0.1% Asian, 0.6% from other races, and 1.4% from two or more races. Those of Hispanic or Latino origin made up 1.8% of the population. In terms of ancestry, 48.6% were German, 20.6% were Czech, 11.7% were Dutch, 7.8% were Irish, 6.1% were Norwegian, and 1.7% were American.
Of the 2,457 households, 25.6% had children under the age of 18 living with them, 55.7% were married couples living together, 5.5% had a female householder with no husband present, 36.0% were non-families, and 32.8% of all households were made up of individuals. The average household size was 2.24 and the average family size was 2.84. The median age was 43.1 years.
The median income for a household in the county was $41,107 and the median income for a family was $51,910. Males had a median income of $34,478 versus $28,464 for females. The per capita income for the county was $20,074. About 10.1% of families and 12.4% of the population were below the poverty line, including 16.7% of those under age 18 and 12.6% of those age 65 or over.
^Journals of the Lewis & Clark Expedition (September 1, 1804), and note 3 ("Bon Homme Island was still on maps in the 1890s, between Bon Homme County, South Dakota, and Knox County, Nebraska. It is now inundated by Lewis and Clark Lake.")
