The basin of the North Platte River takes up the southeastern quarter of Wyoming, plus a finger of land along the tributary Sweetwater River in the center of the state. The courses of the North Platte and Sweetwater determined early fur-trade and emigrant routes. Since that time, the basin’s water and other resources have continued to draw industry, stock raising, dams and irrigation—and people.
Since prehistoric times, people’s lifestyles in what became Natrona County have depended on their livelihoods. Casper was founded in 1888, and county was formed in 1890, shortly before Wyoming became a state. First cattle, then sheep and after 1910, the oil and refining business dominated. An Army Air Corps training base near Casper brought another boost in World War II. Casper College was founded in 1945. Since then, the county has continued to ride the booms and busts of the energy business, but with cultural, health-care and education opportunities growing all the while.