[3] According to the United States Census Bureau, the township has a total area of 34.5 square miles (89.4 km2), all land.

Marshan Township was organized in 1858, and named for the settlers Michael Marsh and his wife Ann.

[4] Hastings has annexed portions of the northern part of the township.

As of the census[1] of 2000, there were 1,263 people, 404 households, and 347 families residing in the township.

9.9% of all households were made up of individuals, and 1.7% had someone living alone who was 65 years of age or older.