Humbug Marsh, a 1.88 square kilometres (0.73 sq mi) wetland in southeastern Wayne County, Michigan, is a constituent element of the Detroit River International Wildlife Refuge.

This slow-flowing river was a hotspot of biological diversity, particularly as a location for fish spawning.

The remnant marsh is classified as a place of "importance to threatened, endangered, and vulnerable species and ecological communities.

"[2] Humbug Marsh is located on the Downriver shoreline of the Detroit River, straddling the boundary line between Gibraltar and Trenton in southeastern Wayne County, Michigan.

[2] The Humbug Marsh parking lot is located at 5437 West Jefferson Avenue, Trenton, Michigan.