Geography According to the United States Census Bureau, the township has a total area of 93.3 km² (36.0 mi²). 83.9 km² (32.4 mi²) of it is land and 9.4 km² (3.6 mi²) of it is water. The total area is 10.08% water.
Demographics As of the census of 2000, there are 20,627 people, 7,086 households, and 5,796 families residing in the township. The population density is 245.9/km² (636.9/mi²). There are 7,678 housing units at an average density of 91.5/km² (237.1/mi²). The racial makeup of the township is 97.22% White, 1.02% African American, 0.28% Native American, 0.44% Asian, 0.03% Pacific Islander, 0.19% from other races, and 0.82% from two or more races. 1.14% of the population are Hispanic or Latino of any race.
There are 7,086 households out of which 43.8% have children under the age of 18 living with them, 73.7% are married couples living together, 5.3% have a female householder with no husband present, and 18.2% are non-families. 13.9% of all households are made up of individuals and 3.5% have someone living alone who is 65 years of age or older. The average household size is 2.88 and the average family size is 3.20.
In the township the population is spread out with 29.6% under the age of 18, 5.5% from 18 to 24, 34.1% from 25 to 44, 24.5% from 45 to 64, and 6.3% who are 65 years of age or older. The median age is 36 years. For every 100 females there are 103.8 males. For every 100 females age 18 and over, there are 103.8 males.
The median income for a household in the township is $75,960, and the median income for a family is $81,351. Males have a median income of $56,671 versus $34,111 for females. The per capita income for the township is $30,283. 2.4% of the population and 1.5% of families are below the poverty line. Out of the total people living in poverty, 2.9% are under the age of 18 and 4.2% are 65 or older.