| County: | Tripp County |
| State: | South Dakota |
| Founded Year: | 1873 (created) 1909 (organized) |
| Seat Wl: | Winner |
| Largest City Wl: | Winner |
| Area Total Sq Mi: | 1618 |
| Area Land Sq Mi: | 1612 |
| Area Water Sq Mi: | 5.1 |
| Area Percentage: | 0.3 |
| Population As Of: | 2020 |
| Population Total: | 5624 |
| Pop Est As Of: | 2023 |
| Population Est: | 5621 |
| Population Density Sq Mi: | auto |
| Time Zone: | Central |
| Web: | http://trippcounty.us/ |
| Ex Image: | Tripp County, SD courthouse from S 1.JPG |
| Ex Image Cap: | Tripp County courthouse in Winner |
| District: | At-large |
Tripp County is a county in the U.S. state of South Dakota. As of the 2020 census, the population was 5,624.[1] Its county seat is Winner.[2] The county was created in 1873, and was organized in 1909.[3] It is named for lawyer, judge, and diplomat Bartlett Tripp.
Tripp County lies on the south line of South Dakota. Its south boundary is the Nebraska state line, while its north boundary is the meandering White River. The Keya Paha River flows east-southeasterly through the lower part of the county. The county terrain is composed of rolling hills carved by gullies and drainages.[4] The county terrain generally slopes to the south and east, although its upper portion drops northward into the White River valley. The county's highest point is on the lower part of its west boundary line, at 2552feet ASL.[5] The county has a total area of, of which is land and (0.3%) is water.[6]
As of the 2020 census, there were 5,624 people, 2,233 households, and 1,398 families residing in the county.[7] The population density was . There were 2,762 housing units.
As of the 2010 census, there were 5,644 people, 2,419 households, and 1,509 families in the county. The population density was . There were 3,072 housing units at an average density of . The racial makeup of the county was 83.1% white, 14.0% American Indian, 0.2% Asian, 0.1% black or African American, 0.2% from other races, and 2.4% from two or more races. Those of Hispanic or Latino origin made up 1.1% of the population. In terms of ancestry, 46.8% were German, 10.8% were Irish, 7.7% were Czech, 6.2% were Dutch, and 4.0% were American.
Of the 2,419 households, 26.9% had children under the age of 18 living with them, 50.4% were married couples living together, 8.4% had a female householder with no husband present, 37.6% were non-families, and 34.6% of all households were made up of individuals. The average household size was 2.28 and the average family size was 2.93. The median age was 45.3 years.
The median income for a household in the county was $40,221 and the median income for a family was $49,570. Males had a median income of $35,238 versus $25,323 for females. The per capita income for the county was $21,192. About 12.1% of families and 16.5% of the population were below the poverty line, including 27.4% of those under age 18 and 10.3% of those age 65 or over.
The county contains one area of unorganized territory: Gassman.
Tripp County voters have traditionally voted Republican. In no national election since 1964 has the county selected the Democratic Party candidate (as of 2020). The Democratic Party has not obtained forty percent of the county's vote since Jimmy Carter in 1976.