Marshall County is a county in the U.S. state of South Dakota. As of the 2020 census, the population was 4,306. Its county seat is Britton. The county was created on May 2, 1885, and was named for Marshall Vincent, who homesteaded near Andover, South Dakota.

Geography

Marshall County lies on the north side of South Dakota. Its north boundary line abuts the south boundary line of the state of North Dakota. Its terrain consists of rolling hills, with numerous lakes and ponds in the SE portion. Its terrain slopes to the northeast, and its highest point is near its SE corner, at 2,034 ft ASL. Marshall County has a total area of 886 sqmi, of which 838 sqmi is land and 48 sqmi (5.4%) is water. The county is drained by the Crow Creek, a tributary of the James River, and the Wild Rice River, a tributary of the Red River of the North. A portion of the Lake Traverse Indian Reservation is located in the eastern part of the county.

Major highways

Protected areas

Adjacent counties

Demographics

2020 census

As of the 2020 census, there were 4,306 people, 1,702 households, and 1,131 families residing in the county. The population density was 5.1 PD/sqmi. There were 2,394 housing units.

2010 census

As of the 2010 census, there were 4,656 people, 1,815 households, and 1,154 families in the county. The population density was 5.6 PD/sqmi. There were 2,534 housing units at an average density of 3.0 /mi2. The racial makeup of the county was 85.4% white, 7.6% American Indian, 0.2% black or African American, 0.2% Asian, 5.6% from other races, and 1.1% from two or more races. Those of Hispanic or Latino origin made up 6.8% of the population. In terms of ancestry, 45.6% were German, 30.6% were Norwegian, 6.8% were Swedish, 5.8% were Irish, 5.2% were English, and 2.7% were American. Of the 1,815 households, 24.4% had children under the age of 18 living with them, 52.8% were married couples living together, 6.0% had a female householder with no husband present, 36.4% were non-families, and 31.4% of all households were made up of individuals. The average household size was 2.36 and the average family size was 2.83. The median age was 43.2 years. The median income for a household in the county was $41,023 and the median income for a family was $56,544. Males had a median income of $31,639 versus $26,737 for females. The per capita income for the county was $22,441. About 9.3% of families and 17.1% of the population were below the poverty line, including 27.6% of those under age 18 and 12.8% of those age 65 or over.

Communities

Cities

Towns

Census-designated place

Unincorporated communities

Townships

Politics

Marshall County voters have tended to vote Democratic for the past several decades. In 64% of the national elections since 1960, the county selected the Democratic Party candidate.