Sweetwater County Assessor's Office
David S. Divis
80 W Flaming Gorge Way Suite 122
Green River, WY 82935
Phone: (307) 872-3700
Fax: (307) 872-3998
- Sweetwater County is a county in southwestern Wyoming, United States. As of the 2010 United States Census, the population was 43,806. Its county seat is Green River. By area, it is the largest county in Wyoming. Its southern boundary line abuts the north lines of the states of Colorado and Utah.