According to the 2021 census gazetteer files, Munson Township has a total area of 35.94 square miles (93.08 km2), all land.

As of the 2020 census[1] there were 385 people, 75 households, and 45 families residing in the township.

There were 127 housing units at an average density of 3.53 per square mile (1.36/km2).

The racial makeup of the township was 98.44% White, 0.00% African American, 0.00% Native American, 0.26% Asian, 0.00% Pacific Islander, 0.26% from other races, and 1.04% from two or more races.

40.00% of all households were made up of individuals, and 16.00% had someone living alone who was 65 years of age or older.