Fennville is a city in Allegan County in the U.S. state of Michigan. The population was 1,745 at the 2020 census. Located on M-89 on the boundary between Manlius Township to the north and Clyde Township to the south, Fennville is located about 11 miles (18 km) southeast of the city of Saugatuck and about 13 miles (21 km) west-northwest of the city of Allegan. It is about 13 miles (21 km) south of Holland, about 16 miles (26 km) northeast of South Haven and roughly 40 miles (64 km) miles southwest of Grand Rapids.