[1] The Job Garner-Jacob W. Miller House was listed on the National Register of Historic Places in 1986.

As of the census[1] of 2020, there were 3,463 people, 1,312 households, and 646 families living in the township.

There were 1,462 housing units at an average density of 34.46 per square mile (13.3/km2).

49.6% of Harrison Township residents were employed, working a mean of 38.4 hours per week.

150 housing units were vacant at a density of 3.5 per square mile (1.4/km2).