Isabella County was described by action of the Michigan Territory legislature in 1831, but for purposes of population, revenue, and judicial matters, it was assigned to nearby counties. Its area was partitioned from unorganized territory plus a portion of Mackinac, which had existed as a Territorial County since 1818.
According to the US Census Bureau, the county has a total area of 578 square miles (1,500 km2), of which 573 square miles (1,480 km2) are land and 5.0 square miles (13 km2) (0.9%) are water.[6]
Highways
US 10 – cuts across NE corner of county. Enters at Clare; runs ESE to east county line. Exits to Coleman.
US 127 – runs north–south through the eastern central part of county. Passes Rosebush and Mt. Pleasant, runs SE to Shepherd, then runs south into Gratiot County.
M-20 – runs east–west across lower central part of county. Enters from Remus. Ends at Mt. Pleasant.[7]
(proposed) – I-73 - project in Michigan is inactive
There were 22,425 households, out of which 28.40% had children under the age of 18 living with them, 45.40% were married couples living together, 8.90% had a female householder with no husband present, and 42.00% were non-families. 23.80% of all households were made up of individuals, and 7.30% had someone living alone who was 65 years of age or older. The average household size was 2.55 and the average family size was 3.03.
The county population contained 20.30% under the age of 18, 29.40% from 18 to 24, 23.80% from 25 to 44, 17.40% from 45 to 64, and 9.00% who were 65 years of age or older. The median age was 25 years. For every 100 females there were 91.40 males. For every 100 females age 18 and over, there were 88.60 males.
The median income for a household in the county was $34,262, and the median income for a family was $45,953. Males had a median income of $32,270 versus $24,180 for females. The per capita income for the county was $16,242. 7.40% of families and 20.40% of the population were below the poverty line, including 11.30% of those under age 18 and 7.80% of those age 65 or over.
Government
United States presidential election results for Isabella County, Michigan[14]
The county government operates the jail, maintains rural roads, operates the major local courts, records deeds, mortgages, and vital records, administers public health regulations, and participates with the state in the provision of social services. The county board of commissioners controls the budget and has limited authority to make laws or ordinances. In Michigan, most local government functions — police and fire, building and zoning, tax assessment, street maintenance, etc. — are the responsibility of individual cities and townships.