Location within the state of Michigan. Coordinates: 42°59′24″N 85°50′18″W / 42.99000°N 85.83833°W / 42.99000; -85.83833Coordinates: 42°59′24″N 85°50′18″W / 42.99000°N 85.83833°W / 42.99000; -85.83833. Tallmadge Charter Township is a charter township of Ottawa County in the U.S. state of Michigan. The population was 7,575 at the 2010 census.