Jefferson county is located in southern Oklahoma and calls Waurika its county seat. Waurika, meaning "camp of clear water", was built at the junction of Beaver and Cow creeks and is the site of a Rock Island Railroad Depot which was built in 1912.

Other historic sites in the county include the State Highway 79 Bridge at the Red River, just southwest of Waurika and the Jefferson County Courthouse.

Major waterways in the county include the Red River, which forms the southern boundary, and Waurika Lake, the majority of which lies within the county's northwest sector. The historic Chisholm Trail passes through the county and is closely paralleled by U.S. Highway 81. The trail was a major route for cattle drives on their way to the stockyards in Kansas before the railroads were established. The Chisholm Trail Museum, displaying relics of the era, is located in Waurika.

The county population on July 1, 1999, was 6,518, a decrease of 492 over the 1990 census.