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Pennington County
Sign in to saveAlso known as Pennington County, South Dakota, Pennington County, SD
county in South Dakota, United States of America
Key facts
- Country
- United States
- State
- South Dakota
- Founded
- January 11, 1875 (created), April 19, 1877 (organized)
- Named after
- John L. Pennington
- Seat
- Rapid City
- Largest city
- Rapid City
- Total
- 2,784.459 sq mi (7,211.72 km )
- Land
- 2,776.765 sq mi (7,191.79 km )
- Water
- 7.694 sq mi (19.93 km ) 0.28%
- Estimate 2025
- 116,792
- Density
- 41.777/sq mi (16.130/km )
- Time zone
- UTC−7 ( Mountain )
- Summer dst
- UTC−6 ( MDT )
- Congressional district
- At-large
- Website
- pennco.org
via Wikipedia infobox
~10 min read
Encyclopedic overview
Pennington County is a county in the U.S. state of South Dakota. As of the 2020 census, the population was 109,222, making it the second most populous county in South Dakota, and was estimated to be 116,792 in 2025. Its county seat is Rapid City. The county was created on January 11, 1875, and was organized on April 19, 1877. It is named for John L. Pennington, fifth Governor of Dakota Territory, who held office in 1875 when the county was formed. Pennington County is included in the Rapid City metropolitan statistical area. It is also the location of Mount Rushmore.
History
Excerpted from Wikipedia’s “Pennington County” article, available under the CC BY-SA 4.0 licence.