Thunder Bay River

Thunder Bay River
The Thunder Bay River in Alpena
Physical characteristics
Source 
  locationMcCormick Lake near Atlanta
  coordinates44°57′41″N 84°14′39″W / 44.96139°N 84.24417°W / 44.96139; -84.24417
Mouth 
  location
Thunder Bay in Alpena
  coordinates
45°3′40″N 83°25′33″W / 45.06111°N 83.42583°W / 45.06111; -83.42583
Length75.4 mi (121.3 km)

The Thunder Bay River is a 75.4-mile-long (121.3 km) river in the U.S. state of Michigan. It drains much of Alpena County and Montmorency County, and a small portion of Oscoda County, into Thunder Bay, a bay of Lake Huron, on the eastern side of northern Michigan. The mouth of the river is in the heart of downtown Alpena and is guarded by the Alpena Light Station.