Fennville is a city in Allegan County in the U.S. state of Michigan. The population was 1,398 at the 2010 census.The city is situated on M-89 on the boundary between Manlius Township on the north and Clyde Township on the south. The city of Saugatuck is about seven miles northwest and Allegan is about 13 miles east-southeast.The city and surrounding region is an American Viticultural Area, the Fennville AVA, known for the production of Michigan wine.