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Plan Your Visit

Looking out over the Detroit River


Directions, Address & Contact Info


The Gibraltar Bay Unit is the first unit of the Detroit River IWR to open to the public daily from dawn to dusk. Location is at 28820 East River Rd, Grosse Ile, Mi.

The Humbug Marsh Unit is only open during Open Houses. You can learn more about future events at the Calendar Page

The Refuge office is located on Grosse Ile, the largest island in the Detroit River. It is housed in the Large Lakes Research Station at 9311 Groh Road, Grosse Ile, MI 48138. The office is open Monday – Friday 8:00 a.m. to 4:00 p.m., phone: 734-365-0219.

Detroit River International Wildlife Refuge
Large Lakes Research Station
9311 Groh Road
Grosse Ile, Michigan 48138
Phone: 734-365-0219; Fax: 734-692-7603

View the Detroit River IWR Staff Directory 


The Detroit River International Wildlife Refuge is located along the lower Detroit River and western shoreline of Lake Erie, just 20 miles south of Detroit and 50 miles north of Toledo, Ohio in Wayne and Monroe counties. At this time, because of current staff limitations, the refuge is not open to the public on a daily basis; however, limited public use opportunities are available. Special events, open houses and education programs are offered throughout the year and are based on availability.  

Points of Interest

Humbug Marsh consists of 410 acres of coastal wetlands and represents the last mile of undeveloped shoreline along the U.S. mainland of the Detroit River. The site is home to 154 species of birds, 51 species of fish, 90 species of plants, 7 species of reptiles and amphibians, and 37 species of dragonflies and damselflies. In 2010, the Marsh was designated as Michigan’s only “Wetland of International Importance” by the 1971 Ramsar Convention.

The Humbug Marsh unit of the refuge is the hub of visitor activity. Adjacent to the Marsh is the Refuge Gateway property, a former industrial manufacturing site that is being remediated and restored as an ecological buffer for the Marsh, and the future home of the Detroit River International Wildlife Refuge Visitor Center.

Know Before You Go

The Humbug Marsh Unit is closed to the public at this time. For information about open houses and other events on the refuge please contact Jennie Braatz at or by calling 734-362-7736. 

Sunscreen and insect repellent are strongly recommended.

Last Updated: Jul 18, 2016
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