According to theU.S. Census Bureau, the county has a total area of 718 square miles (1,860 km2), of which 706 square miles (1,830 km2) is land and 12 square miles (31 km2) (1.7%) is water.[5]
TheKalamazoo River oil spill occurred in July 2010 when a pipeline operated byEnbridge (Line 6B) burst and flowed into Talmadge Creek, a tributary of the Kalamazoo River. A six-foot break in the pipeline resulted in the largest inland oil spill, and one of the costliest spills in U.S. history. The pipeline carries diluted bitumen (dilbit), aheavy crude oil from Canada'sAthabasca oil sands to the United States. Following the spill, the volatile hydrocarbon diluents evaporated, leaving the heavier bitumen to sink in the water column. Thirty-five miles of the Kalamazoo River were closed for clean-up until June 2012, when portions of the river were re-opened. On March 14, 2013, the Environmental Protection Agency (EPA) ordered Enbridge to return to dredge portions of the river to remove submerged oil and oil-contaminated sediment.
As of the2020 census, the county had a population of 134,310. The median age was 40.5 years. 22.8% of residents were under the age of 18 and 18.4% of residents were 65 years of age or older. For every 100 females there were 98.0 males, and for every 100 females age 18 and over there were 96.0 males age 18 and over.[11]
67.7% of residents lived in urban areas, while 32.3% lived in rural areas.[13]
There were 54,406 households in the county, of which 28.6% had children under the age of 18 living in them. Of all households, 42.5% were married-couple households, 20.3% were households with a male householder and no spouse or partner present, and 28.7% were households with a female householder and no spouse or partner present. About 30.8% of all households were made up of individuals and 13.3% had someone living alone who was 65 years of age or older.[11]
There were 59,518 housing units, of which 8.6% were vacant. Among occupied housing units, 69.9% were owner-occupied and 30.1% were renter-occupied. The homeowner vacancy rate was 1.6% and the rental vacancy rate was 8.9%.[11]
The2010 United States census[14] indicates Calhoun County had a 2010 population of 136,146. This is a decrease of -1,839 people from the2000 United States census. Overall, the county had a -1.3% growth rate during this ten-year period. In 2010 there were 54,016 households and 35,220 families in the county. Thepopulation density was 192.8 per square mile (74.4 square kilometers). There were 61,042 housing units at an average density of 86.4 per square mile (33.4 square kilometers). Theracial and ethnic makeup of the county was 79.8% White, 10.7% Black or African American, 0.5% Native American, 1.6% Asian, 4.5% Hispanic or Latino, 0.1% from other races, and 2.7% from two or more races.[14]
There were 54,016 households, out of which 31.2% had children under the age of 18 living with them, 45.3% werehusband and wife families, 14.6% had a female householder with no husband present, 34.8% were non-families, and 28.8% were made up of individuals. The average household size was 2.44 and the average family size was 2.98.[14]
In the county, the population was spread out, with 24.2% under age of 18, 9.3% from 18 to 24, 24.0% from 25 to 44, 27.7% from 45 to 64, and 14.8% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 95.5 males. For every 100 females age 18 and over, there were 92.5 males.[14]
The2010 American Community Survey 1-year estimate indicates the median income for a household in the county was $42,921 and the median income for a family was $49,964. Males had a median income of $25,712 versus $18,298 for females. Theper capita income for the county was $20,661. About 11.7% of families and 16.2% of the population were below thepoverty line, including 23.9% of those under the age 18 and 5.8% of those age 65 or over.[14]
The county government operates thejail, maintains rural roads, operates the major local courts,keeps files of deeds and mortgages, maintainsvital records, administerspublic health regulations, andparticipates with the state in the provision of welfare and other social services. Thecountyboard of commissioners controls the budget but has only limited authority to make laws or ordinances. InMichigan, most local government functions — police and fire, building and zoning, tax assessment, streetmaintenance, etc. — are the responsibility of individual cities and townships.
Calhoun County is a swing county in presidential elections. Beginning in 1964, it has voted for the winner of the national election every time except in1976 (instead backing native MichiganderGerald Ford),2000, and2020.