[11] The township has a small northeastern coastline along Lake Charlevoix.

As of the census[2] of 2000, there were 1,492 people, 535 households, and 418 families residing in the township.

There were 632 housing units at an average density of 24.7 per square mile (9.5/km2).

18.5% of all households were made up of individuals, and 7.9% had someone living alone who was 65 years of age or older.

Marion Township is served almost entirely by Charlevoix Public Schools to the north in the city of Charlevoix, while a very small portion of the southern edge of the township is served by Ellsworth Community School in the village of Ellsworth to the south in Antrim County.