Much of Union Township is protected by the Traverse City Management Unit of the Pere Marquette State Forest.

As of the census[1] of 2000, there were 417 people, 157 households, and 116 families residing in the township.

There were 222 housing units at an average density of 6.2 per square mile (2.4/km2).

The racial makeup of the township was 97.60% White, 1.20% Native American, and 1.20% from two or more races.

20.4% of all households were made up of individuals, and 2.5% had someone living alone who was 65 years of age or older.