Seminole County, Oklahoma
Before Oklahoma's admission as a state, the county was the entire small portion of Indian Territory allocated to the Seminole people, who were removed from Florida in the 1820s. It is notable for the Greater Seminole Field, one of the most important oil fields ever found, which is still producing. It extends into nearby counties. In the early years of the oil boom, workers and adventurers flooded into the county, rapidly tripling the population. As oil production later declined, jobs and residents left.