Sweetwater County comprises the Rock Springs, Green River, Wyoming Micropolitan Statistical Area.

Carter of Fort Bridger[5] In 1869, the newly established legislature of the Wyoming Territory renamed the county for the Sweetwater River.

As of the 2000 United States Census,[10] of 2000, there were 37,613 people, 14,105 households, and 10,099 families in the county.

23.60% of all households were made up of individuals, and 6.90% had someone living alone who was 65 years of age or older.

As of the 2010 United States Census, there were 43,806 people, 16,475 ;households, and 11,405 families in the county.

[12] In terms of ancestry, 22.4% were German, 19.0% were English, 13.0% were Irish, 7.4% were Italian, and 4.4% were American.

"[27] Additionally, students in McKinnon, Wyoming may choose to attend DSD schools.

[27] Sweetwater is also home to Western Wyoming Community College which is located in Rock Springs.

Sweetwater County was a Democratic stronghold in Wyoming until recent years, voting Democratic in eleven consecutive presidential elections between 1928 and 1968, after supporting Progressive Robert La Follette Sr. in 1924.

Nonetheless, no Democratic presidential candidate has won Sweetwater County since Bill Clinton in 1996.

Sweetwater County is served by two print publications: Rock Springs Daily Rocket-Miner and The Green River Star (a weekly newspaper published in Green River).

Sweetwater County is served by a hyperlocal news websites, SweetwaterNOW.com and wyo4news.com.