Tishomingo is the largest city in, and the county seat of, Johnston County, Oklahoma, United States. The population was 3,101 as of the 2020 Census, an increase of 2.2% over the population of 3,034 reported at the 2010 census. It was the first capital of the Chickasaw Nation, from 1856 until Oklahoma statehood in 1907. The city is home to Murray State College, a community college with an annual enrollment of 3,015 students. Tishomingo is part of the Texoma region.