| Official Name: | Overisel Township, Michigan |
| Settlement Type: | Township |
| Pushpin Map: | Michigan |
| Pushpin Label: | Overisel Township |
| Pushpin Label Position: | left |
| Pushpin Map Caption: | Location within the state of Michigan |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Michigan |
| Subdivision Type2: | County |
| Subdivision Name2: | Allegan |
| Unit Pref: | Imperial |
| Area Total Km2: | 92.5 |
| Area Land Km2: | 92.3 |
| Area Water Km2: | 0.2 |
| Population As Of: | 2020 |
| Population Total: | 3113 |
| Population Density Km2: | 33.94 |
| Timezone: | Eastern (EST) |
| Utc Offset: | -5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | -4 |
| Elevation M: | 201 |
| Elevation Ft: | 659 |
| Coordinates: | 42.7183°N -85.9631°W |
| Blank Name: | FIPS code |
| Blank Info: | 26-61820[1] |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 1626872 |
Overisel Township is a civil township of Allegan County in the U.S. state of Michigan. The population was 3,113 at the 2020 census.[2]
Overisel was named after the Dutch province of Overijssel.[3] Overisel is the birthplace of mathematician George David Birkhoff, best known for what is now called the ergodic theorem.
According to the United States Census Bureau, the township has a total area of 92.5km2, of which 92.3sqkm is land and 0.2sqkm, or 0.22%, is water.[2]
As of the census of 2000, there were 2,594 people, 869 households, and 730 families residing in the township. The population density was 72.4sp=usNaNsp=us. There were 897 housing units at an average density of 25.0 per square mile (9.7/km). The racial makeup of the township was 96.92% White, 0.04% African American, 0.04% Native American, 0.50% Asian, 2.20% from other races, and 0.31% from two or more races. Hispanic or Latino of any race were 3.39% of the population.
There were 869 households, out of which 42.7% had children under the age of 18 living with them, 77.7% were married couples living together, 3.5% had a female householder with no husband present, and 15.9% were non-families. 13.8% of all households were made up of individuals, and 6.3% had someone living alone who was 65 years of age or older. The average household size was 2.98 and the average family size was 3.30.
In the township the population was spread out, with 30.9% under the age of 18, 7.5% from 18 to 24, 30.8% from 25 to 44, 20.1% from 45 to 64, and 10.8% who were 65 years of age or older. The median age was 34 years. For every 100 females, there were 103.3 males. For every 100 females age 18 and over, there were 104.0 males.
The median income for a household in the township was $52,857, and the median income for a family was $56,964. Males had a median income of $39,594 versus $26,982 for females. The per capita income for the township was $18,831. About 1.5% of families and 2.3% of the population were below the poverty line, including none of those under age 18 and 15.4% of those age 65 or over.