People have existed in southwestern Wyoming for thousands of years, yet most lacked the heartiness to settle there. Fur trappers were among the first to explore the area's natural resources, but more importantly, they mapped the frontier, allowing westward expansion along the Oregon, California, Mormon, Cherokee, and Overland trails. Sweetwater County was formed in 1868, with the organization of the Wyoming Territory, and South Pass City became the county seat. A waning gold industry in South Pass caused the county seat to be relocated to Sweetwater County in 1875. Ironically, the Sweetwater River and South Pass City would end up in Fremont County and, in typical boom-and-bust fashion, gold went out and coal was in. Miners were needed, so coal camps were established and workers ultimately settled in Sweetwater County with their families. In the 1930s, Rock Springs became a melting pot, boasting 56 nationalities at the high school. The oil, natural gas, and mining industries continue this boom-and-bust cycle even today.