The township was organized with the name Waterloo in 1860 and renamed Elmwood by the state legislature in 1863.

[4] According to the United States Census Bureau, the township has a total area of 35.5 square miles (92 km2), all land.

As of the census[1] of 2000, there were 1,213 people, 470 households, and 343 families residing in the township.

There were 515 housing units at an average density of 14.5 per square mile (5.6/km2).

23.6% of all households were made up of individuals, and 10.9% had someone living alone who was 65 years of age or older.