The Rock of Ages Light is a U.S. Coast Guard lighthouse

Lighthouse

A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses or, in older times, from a fire, and used as an aid to navigation for maritime pilots at sea or on inland waterways....

 on a small rock outcropping (50 feet (15.2 m) X 200 feet (61 m)) approximately 2.25 mi (3.6 km) miles west of Washington Island

Washington Island (Michigan)

Washington Island is an uninhabited island in Lake Superior. It is within the boundary of Keweenaw County and Isle Royale National Park, a national park located within the U.S. state of Michigan. It is the westernmost point marked on most maps of the elongated archipelago that makes up this park...

 and 3.5 mi (5.6 km) west of Isle Royale, in Keweenaw County, Michigan

Keweenaw County, Michigan

-Demographics:As of the census of 2000, there were 2,301 people, 998 households, and 604 families residing in the county. The population density was 4 people per square mile . There were 2,327 housing units at an average density of 4 per square mile...

 (see map below). It is an active aid to navigation.
The period between 1852 and the beginning of the 20th century saw great activity on the Great Lakes

Great Lakes

The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...

 by the United States Lighthouse Board

United States Lighthouse Board

The United States Lighthouse Board was the agency of the US Federal Government that was responsible for the upkeep and maintenance of all lighthouses in the United States...

.