On March 9, 1865, Mason was incorporated as a village and during the 19th century, Mason enjoyed being the center of Ingham County activity. While Lansing eventually became the state capital, Mason remained the Ingham County Seat, making Michigan the only state in the country with a capital city that is not also the county seat. Mason’s city center is the historic Ingham County Courthouse, and two historic churches are the cornerstones of the downtown courthouse square. This downtown city block is the location of numerous events, including the annual Sun Dried Music Festival in late August, seasonal Farmer’s Markets, live music, parades and holiday celebrations.
Source : Curt Smith, “Mason kicks off 150th birthday celebration”, Lansing State Journal, March 9, 2015.