Ironwood, Michigan, at the Wisconsin state line, is 26 miles (42 km) to the west on US 2.

State highway M-64 passes through the center of Marenisco, leading south 9 miles (14 km) to the Wisconsin border.

The community of Marenisco was listed as a newly organized census-designated place for the 2010 census, meaning it now has officially defined boundaries and population statistics for the first time.

[5] According to the United States Census Bureau, the Marenisco CDP has an area of 3.4 square miles (8.9 km2), all of it land.

The community is bounded to the east by the Presque Isle River, which flows to Lake Superior in northeastern Gogebic County.