Eureka is an unincorporated community in the northeast part of the township at. The Eurekapost office, with ZIP code 48833, provides PO box service for the community. The area was first settled in 1836 by John Ferdon, a member of the Rochester Colony, which also founded a settlement at Duplain in Duplain Township, adjacent to the east. Ferdon held land in both township. Before it was platted, the settlement was known as Williamsport, for pioneer settler Clark Williams; Barrington, for another settler J.A. Barrington; and Swizzletown, "which suggested the inhabitants were bibulous". It was platted in 1857 by Isaac Eagles and Mr. Barrington with the name Greenbush, after the township. A post office with that name had been established on January 29, 1844. On May 9, 1867, the post office and community were renamed Eureka, the name given by Edward Stark "as a place where he had found and others would find a fine place for doing business."
Geography
Greenbush Township is located in northern Clinton County and is bordered by Gratiot County to the north. U.S. Route 127 crosses the township, leading north to Mount Pleasant and south to Lansing. According to the United States Census Bureau, the township has a total area of, of which is land and, or 0.77%, is water.
Demographics
As of the census of 2000, there were 2,115 people, 743 households, and 621 families residing in the township. The population density was 60.0 per square mile. There were 759 housing units at an average density of 21.5 per square mile. The racial makeup of the township was 98.77% White, 0.19% African American, 0.05% Native American, 0.19% Asian, 0.05% Pacific Islander, 0.33% from other races, and 0.43% from two or more races. Hispanic or Latino of any race were 1.75% of the population. There were 743 households, out of which 37.0% had children under the age of 18 living with them, 74.3% were married couplesliving together, 6.2% had a female householder with no husband present, and 16.3% were non-families. 14.5% of all households were made up of individuals, and 6.5% had someone living alone who was 65 years of age or older. The average household size was 2.82 and the average family size was 3.11. In the township the population was spread out, with 26.6% under the age of 18, 6.8% from 18 to 24, 28.9% from 25 to 44, 27.0% from 45 to 64, and 10.8% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 101.8 males. For every 100 females age 18 and over, there were 99.6 males. The median income for a household in the township was $53,021, and the median income for a family was $57,721. Males had a median income of $40,391 versus $30,429 for females. The per capita income for the township was $21,453. About 1.7% of families and 3.3% of the population were below the poverty line, including 2.7% of those under age 18 and 3.9% of those age 65 or over.
