According to the United States Census Bureau, the township has a total area of, of which is land and is water.
Communities
Carleton is a village in the west-central portion of the township.
Clark City was built around a stave mill along Swan Creek. It had a post office from 1855 until 1866.
Demographics
As of the census of 2000, there were 7,610 people, 2,801 households, and 2,125 families residing in the township. The population density was 220.0 per square mile. There were 2,942 housing units at an average density of 85.0 per square mile. The racial makeup of the township was 97.08% White, 0.32% African American, 0.32% Native American, 0.22% Asian, 0.01% Pacific Islander, 0.33% from other races, and 1.72% from two or more races. Hispanic or Latino of any race were 1.75% of the population. There were 2,801 households, out of which 35.6% had children under the age of 18 living with them, 61.4% were married couplesliving together, 9.7% had a female householder with no husband present, and 24.1% were non-families. 20.3% of all households were made up of individuals, and 7.1% had someone living alone who was 65 years of age or older. The average household size was 2.72 and the average family size was 3.13. In the township the population was spread out, with 27.5% under the age of 18, 8.3% from 18 to 24, 29.4% from 25 to 44, 24.5% from 45 to 64, and 10.1% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 100.8 males. For every 100 females age 18 and over, there were 97.8 males. The median income for a household in the township was $54,439, and the median income for a family was $61,020. Males had a median income of $47,892 versus $25,699 for females. The per capita income for the township was $24,271. About 4.6% of families and 6.3% of the population were below the poverty line, including 9.0% of those under age 18 and 4.7% of those age 65 or over.
History
The township was named in honor of Arba Ash, a resident of Wayne County who had an appointment from the governor to establish towns and counties.