Tecumseh is a city in Lenawee County in the U.S. state of Michigan, near the River Raisin. Tecumseh is about 60 miles southwest of Detroit, 25 miles south of Ann Arbor, and 40 miles north of Toledo, Ohio. The main street of downtown is Chicago Boulevard, also designated as M-50. It crosses the River Raisin a few miles east of M-52. The city is surrounded on three sides by Tecumseh Township, but the two are politically independent. Raisin Township borders the southern edge of the city.