The Carp River of Mackinac and Chippewa Counties is a federally designated Wild and Scenic River in the Upper Peninsula. Approximately 45 miles (70 km) long, the river rises near Trout Lake, Michigan in Chippewa County. The river then flows southeast into Mackinac County, continuing in this county until it flows into St. Martin Bay, Lake Huron. 21.7 miles (35 km) of the river were added to the National Wild and Scenic Rivers System in 1992.
The Carp River flows for much of its length through the eastern region of the Hiawatha National Forest. A central portion of the river, near M-123, flows through the Mackinac Wilderness, jointly preserved by the U.S. Forest Service and the Great Lakes Indian Fish & Wildlife Commission of the Ojibwa Indians.
In contrast to much of the Upper Peninsula, the Carp River's watershed is relatively flat, and there are no waterfalls on the river. It is often used by canoeists. Fishermen can find brook trout, brown trout, and rainbow trout in the river in summer, with some salmon in fall.