Green River is located in Sweetwater County (of which it is the county seat) in southwestern Wyoming between Evanston and Rock Springs along Highway 530 on the banks of the Green River near Flaming Gorge National Recreation Area.
The population estimate for July 1, 1998 was 13,059, an increase of 348 since 1990.
Rich in history, in prehistoric times the landscape was swampy and inhabited by great dinosaurs. Thousands of years later Native Americans, mostly Shoshone and Ute, claimed the land.
The first "White Men" in the area were "Mountain Men". Several major emigrant trails passed through the county including the Oregon, California, Mormon, Overland, and Cherokee Trails, as well as the 1861 transcontinental telegraph line and Ben Holladay's Central Overland Express stage line. Vitally important to the history of the county was the coming of the transcontinental railroad in 1868.