Imlay City is a city in Lapeer County in the U.S. state of Michigan. The population was 3,707 at the 2020 census. In 1836, Connecticut businessman William H. Imlay began purchases areas of the forest here, and when the township was organized in 1850, it was named after him. In 1870, the Port Huron & Lake Michigan Railroad began building rail lines through the area, and chief engineer Charles Palmer purchased land in order to build a market and hotel. A post office began operating here on December 12, 1870 with Edward Palmer serving as the first postmaster. The community grew quickly to include 15 stores, a grain elevator, and several mills. In 1871, the community incorporated as a village named Imlay City.