Tecumseh is a city in Pottawatomie County, Oklahoma, United States. The population was 6,457 at the 2010 census, a 5.9 percent increase from 6,098 at the 2000 census. It was named for the noted Shawnee chief, Tecumseh, and was designated as the county seat at Oklahoma's statehood. A county-wide election moved the seat to Shawnee in 1930.
A 320-acre (129.5 hectare) site was opened for settlement September 23, 1891, as a result of the land run into reservations of the Sac and Fox, Kiowa, Kickapoo, Shawnee and Pottawatomi peoples. The townsite, named Tecumseh by a U.S. Army Major, had been designated as the seat of County "B" in the newly formed Oklahoma Territory by the Department of the Interior on July 17, 1891. A post office was established in the town on September 18, 1891.
In 1903 the Atchison, Topeka and Santa Fe Railway began serving Tecumseh's surrounding agricultural region, in which cotton was the main crop. Cotton production dropped in the 1920s because of depressed prices and a boll weevil infestation. The population dropped after 1930, because many townspeople moved away to earn a living elsewhere.
In 2002, the U.S. Supreme Court evaluated whether it was lawful to require students from Tecumseh schools to take drug tests in order to participate in extracurricular activities. In a 5-4 decision, the court ruled that the tests were allowable in Board of Education v. Earls.