The unincorporated community of South Troy is in Zumbro Township.

As of the census[1] of 2000, there were 715 people, 283 households, and 217 families residing in the township.

There were 322 housing units at an average density of 10.2 per square mile (3.9/km2).

There were 283 households, out of which 29.7% had children under the age of 18 living with them, 71.4% were married couples living together, 4.6% had a female householder with no husband present, and 23.0% were non-families.

19.8% of all households were made up of individuals, and 3.5% had someone living alone who was 65 years of age or older.