Sweetwater County lies in the southwest portion of Wyoming in the United States. At the 2010 census (2010 census) the county recorded 43,806 residents. Green River serves as the county seat, while nearby Rock Springs is the region's largest city and economic center; the county's southern border meets the northern lines of Colorado and Utah.

Geography and environment

The county covers varied high‑desert terrain and river valleys. The Green River flows through the area and has shaped local settlement and industry. Elevated plateaus, badlands, and basins provide habitat for sagebrush steppe wildlife; parts of the landscape are used for grazing, energy development, and public outdoor recreation.

Economy and transportation

Sweetwater County's economy is closely tied to natural resources. Large deposits of trona and other minerals, plus coal, oil and natural gas operations, have been important employers. Transportation routes such as Interstate 80 and freight lines of the transcontinental railroad cross the county, connecting local industries to national markets.

History and communities

Indigenous peoples inhabited the region prior to Euro‑American exploration and settlement. Arrival of the railroad and the mining industry in the late 19th century brought rapid growth; the county contains several historic towns and has been the site of notable events in western labor and immigration history. Communities include Green River and Rock Springs, together with smaller towns and dispersed rural settlements.

Recreation and scenic resources attract visitors for fishing, boating, hunting and off‑road travel; federal and state lands offer trails and access to natural features. The combination of energy production, rail and highway corridors, and outdoor amenities gives Sweetwater County a prominent role in Wyoming's economy and landscape.