In 1975, plesiosaur fossils dating to the Cretaceous Period (ca. 110 million years ago) were discovered in Butte County. In the 1980s, a 90-million-year-old fossil of a clawless lobster was discovered. A Tyrannosaurus rex skeleton was found in 1981.
The early human history of the Belle Fourche River Valley has been traced to about 3000 BC. The first people of the area were Native Americans who resided on the northwestern plains of North America. The earliest known evidence of human activity in the area dates to the Middle Plains Archaic Period of the Plains Indians (ca. 3000–1500 BC). Traces of tipi rings dating from this period have been found. In 1979 and 1980, archeologists excavated a fortified and previously inhabited site west of Belle Fourche that dated to AD 1000. This site was called the Smiley-Evans Site and had been recorded in 1959. Until 1984, only 47 archaeological sites had been recorded, but after the excavation of the Smiley-Evans Site, several investigations were undertaken. As of 1989[update], 199 archaeological sites had been discovered in the county.[4]
Geography
Butte County lies on the west edge of South Dakota. Its northwestern boundary line abuts the eastern boundary line of the state of Montana, and its southwestern boundary line abuts the eastern boundary line of the state of Wyoming. The Butte County terrain consists of semi-arid rolling hills cut by drainages oriented NW-SE. A relatively small portion of the area is dedicated to agriculture, including the employment of center pivot irrigation.[5] The terrain slopes to the southeast, and its highest point is on the western boundary line near the SW corner: 3,865 ft (1,178 m) ASL.[6]
The county has a total area of 2,266 square miles (5,870 km2), of which 2,250 square miles (5,800 km2) is land and 16 square miles (41 km2) (0.7%) is water.[7]
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 10,243 people.
2010 census
As of the census of 2010, there were 10,110 people, 4,160 households, and 2,786 families in the county. The population density was 4.5 inhabitants per square mile (1.7/km2). There were 4,621 housing units at an average density of 2.1 units per square mile (0.81 units/km2). The racial makeup of the county was 94.2% white, 1.9% American Indian, 0.2% black or African American, 0.2% Asian, 0.1% Pacific islander, 0.8% from other races, and 2.6% from two or more races. Those of Hispanic or Latino origin made up 3.0% of the population. In terms of ancestry, 40.9% were German, 16.6% were Irish, 15.7% were Norwegian, 10.4% were English, and 5.2% were American.
Of the 4,160 households, 30.5% had children under the age of 18 living with them, 52.3% were married couples living together, 9.8% had a female householder with no husband present, 33.0% were non-families, and 28.5% of all households were made up of individuals. The average household size was 2.40 and the average family size was 2.92. The median age was 41.1 years.
The median income for a household in the county was $39,041 and the median income for a family was $52,829. Males had a median income of $37,429 versus $25,273 for females. The per capita income for the county was $20,418. About 11.5% of families and 15.6% of the population were below the poverty line, including 25.0% of those under age 18 and 8.9% of those age 65 or over.
Like most of South Dakota, Butte County is a Republican stronghold. No Democratic presidential candidate has carried Butte County since Franklin D. Roosevelt in 1932. Although Roosevelt in the following election and Lyndon Johnson in 1964, respectively, came within six and fourteen votes of claiming the county during landslide Democratic victories, apart from these instances, no Democratic presidential candidate since 1920 has reached forty percent of the county's vote.
United States presidential election results for Butte County, South Dakota[19]
United States
South Dakota
