South Haven is a city in the U.S. state of Michigan. Most of the city is in Van Buren County, although a small portion extends into Allegan County. The population was 3,964 at the 2020 census. Because of its position on Lake Michigan, at the mouth of the Black River, South Haven has always been a port city. During settlement, major ship lines stopped there, both passenger and freight. In the early 1900s South Haven became a resort town, sometimes referred to as "The Catskills of the Midwest."