Jefferson lies inside southern Oklahoma possession going back before statehood - 7th May 2007 when Waurika established itself as the county seat while cities like Terral, Ringling and Ryan exist scattered across its 1332 km² (515 sq mi) area. Data from the UUnited States Census Bureau estimates; was derived that an estimated 5 255 inhabitants called Jefferson home in 2019 classifying Jefferson amongst some of less densely populated counties found encompassed alongside Oklahomas boundary lines.