The southern border of the township is the shore of Lake Michigan.

Garfield Township is the location of the northernmost point of Lake Michigan.

The location, near Naubinway, was designated as a Michigan State Historic Site named "the Northernmost Point of Lake Michigan" on April 14, 1964.

This point was used to draw the westernmost boundary of the Michigan Territory when it was created in 1805.

[7] According to the United States Census Bureau, Garfield Township has a total area of 137.56 square miles (356.28 km2), of which 134.52 square miles (348.41 km2) are land and 3.04 square miles (7.87 km2) (2.26%) are water.