Thornapple Township is located in the northwest corner of Barry County.

Michigan state highway M-37 passes through the center of the township, leading southeast 11 miles (18 km) to Hastings, the county seat, and 22 miles (35 km) north to downtown Grand Rapids.

[4] As of the census[1] of 2000, there were 6,685 people, 2,292 households, and 1,835 families residing in the township.

There were 2,383 housing units at an average density of 67.1 per square mile (25.9/km2).

16.6% of all households were made up of individuals, and 6.5% had someone living alone who was 65 years of age or older.