Location

The Thunder Bay NMS/UP encompasses 448 square miles of northwest Lake Huron, off the northeast coast of Michigan's Lower Peninsula. The northern and southern boundaries are marked by the northern and southern limits of Alpena County, and the sanctuary extends east from the lakeshore to longitude 83 degrees west. The largest city in the vicinity is Alpena.

Area view of the Thunder Bay National Marine Sanctuary and Underwater Preserve. Click here for a view of the sanctuary/preserve boundaries.