Ludington is a city in the U.S. state of Michigan. It is the county seat and the largest city in Mason County. The population was 7,655 at the 2020 census. The city is located at the mouth of the Pere Marquette River at Lake Michigan. Nearby are Ludington State Park, Nordhouse Dunes Wilderness, and Manistee National Forest. Ludington is the home port of the SS Badger, a vehicle and passenger ferry with daily service in the summer across Lake Michigan to Manitowoc, Wisconsin.