The Village of Lennon is located along the boundary of Shiawassee and Genesee Counties, with a portion of the village in each county. The Shiawassee County side is part of Venice Township and the Genesee County side is part of Clayton Township. The village is bisected by M-13, a state highway that runs along the county line and extends from the I-69 interchange just south of Lennon to a point 77 mile north, located just south of the City of Standish. East/west connections are provided by M-21 a state highway a mile north of the village and I-69, and US Interstate highway located a mile south of the village.
The village was founded by Peter Lennon. He got the Grand Trunk Western Railroad routed through the settlement and a depot built there. He built a grain elevator, which is followed by other businesses. A post office was established in Genesee County in July 1880 with Lennon as the first postmaster. The office was transferred to Shiawassee County in February 1889.
The village was incorporated in the 1970's.
