Shawnee is a city in and the county seat of Pottawatomie County, Oklahoma, United States. The population was 29,857 in 2010, a 4.9 …Shawnee is a city in and the county seat of Pottawatomie County, Oklahoma, United States. The population was 29,857 in 2010, a 4.9 percent increase from the figure of 28,692 in 2000. The city is part of the Oklahoma City-Shawnee Combined Statistical Area and the principal city of the Shawnee Micropolitan Statistical Area.