Excluding the city of Sylvania, the remainder of the township had a population of 31,668 in 2020.

Located in the northern part of the county, it borders the following townships and municipalities: The city of Sylvania lies in northern Sylvania Township.

The Ottawa River and Ten Mile Creek both flow through the township.

[6] Sylvania township is a limited home rule township governed by a three-member board of trustees, who are elected in November of odd-numbered years to a four-year term beginning on the following January 1.

[8] The following highways are important transportation arteries in Sylvania Township: