Tecumseh, MI is currently utilizing one area code which is 517. Area code 517 is one of three original area codes assigned to Michigan, including Adrian, MI, and put into service on January 1, 1947.
In addition to Tecumseh, MI area code 517 serves south-central Michigan, including Lansing which is the capital of Michigan, along with the larger cities and communities of Clinton, East Lansing, Jackson, and Okemos, in addition to many smaller communities within the service area.
Tecumseh, MI is located in Lenawee County and observes the Eastern Time Zone. View our Times by Area Code tool.