Pennington County, South Dakota

Pennington County covers 2,784 square miles, making it the second-largest county in South Dakota by area. The western part of the county lies in the Black Hills, a forested mountain range, while the eastern part is in the Great Plains. The county's elevation ranges from about 2,000 feet in the east to over 7,000 feet at Harney Peak (now Black Elk Peak) in the Black Hills. The climate is semi-arid, with cold winters and warm summers; Rapid City receives about 16 inches of precipitation annually. The county is drained by the Cheyenne River and its tributaries, including Rapid Creek and Box Elder Creek.¹

Pennington County was created in 1875 and named after John L. Pennington, the governor of Dakota Territory at the time. The discovery of gold in the Black Hills in 1874 brought a rush of settlers, and Rapid City was founded in 1876 as a gateway to the gold fields. The county's early economy relied on mining, agriculture, and later tourism. Mount Rushmore was carved between 1927 and 1941, drawing visitors from around the world. The county also played a role in the Cold War, with Ellsworth Air Force Base established in 1942, which remains a major employer today.

According to the 2020 census, Pennington County had a population of 109,222, a 12.4% increase from 2010. The racial makeup was 82.5% White, 8.1% Native American, 2.3% Black, and 1.4% Asian. The county's economy is diverse, with major sectors including healthcare, education, retail, and tourism. Rapid City serves as a regional hub for medical services, with Monument Health and the VA Black Hills Health Care System. Ellsworth Air Force Base contributes significantly to the local economy, employing over 4,000 military and civilian personnel. Tourism is also vital, with attractions like Mount Rushmore, Badlands National Park (partially in the county), and the Black Hills National Forest drawing millions of visitors annually.²

Pennington County is governed by a five-member board of county commissioners, elected from districts. The county provides law enforcement through the Pennington County Sheriff's Office, which operates the county jail and patrols unincorporated areas. The county seat, Rapid City, is the second-largest city in South Dakota and hosts the county courthouse and administrative offices. Major transportation routes include Interstate 90, which runs east-west through the county, and U.S. Highway 16, which connects Rapid City to Mount Rushmore. Rapid City Regional Airport offers commercial flights to major hubs. The county also maintains a network of rural roads and bridges, with ongoing infrastructure projects to address growth.³

Pennington County has several lesser-known features. The county contains the town of Keystone, which is the nearest town to Mount Rushmore and has a population of fewer than 300. The county is also home to the Minuteman Missile National Historic Site, which preserves a Cold War-era intercontinental ballistic missile silo. The county's eastern edge includes part of Badlands National Park, known for its rugged terrain and fossil beds. The county has a notable history of paleontological discoveries, including the remains of ancient marine reptiles. Additionally, the county hosts the annual Sturgis Motorcycle Rally, which, despite being named for neighboring Meade County, has significant economic impact on Pennington County due to its proximity. The county also has a unique geological feature: the Badlands Wall, a dramatic erosion escarpment that runs through the county.⁴

Black Hills

A small, isolated mountain range in western South Dakota, sacred to the Lakota people.

Mount Rushmore

A sculpture of four U.S. presidents carved into granite in the Black Hills.

Ellsworth Air Force Base

A U.S. Air Force base near Rapid City, home to B-1B Lancer bombers.