Mecosta County is a county located in the U.S. state of Michigan. As of the 2010 census, the population was 42,798. The county seat is Big Rapids.
According to the U.S. Census Bureau, the county has a total area of 571 square miles (1,480 km), of which 555 square miles (1,440 km) is land and 16 square miles (41 km) (2.8%) is covered by water.
As of the census of 2000, 40,553 people, 14,915 households, and 9,888 families resided in the county. The population density was 73 people per square mile (28/km²). The 19,593 housing units averaged 35 per square mile (14/km²). The racial makeup of the county was 92.68% White, 3.60% Black or African American, 0.64% Native American, 0.87% Asian, 0.04% Pacific Islander, 0.37% from other races, and 1.79% from two or more races. About 1.28% of the population were Hispanics or Latinos of any race; 25.5% were of German, 20.6% English, 9.2% Irish, and 5.3% Polish ancestry according to the 2010 American Community Survey. 95.9% spoke English, 1.7% Spanish, and 1.1% German as their first language.
Of the 14,915 households, 29.10% had children under the age of 18 living with them, 53.30% were married couples living together, 9.30% had a female householder with no husband present, and 33.70% were not families. About 24.50% of all households were made up of individuals, and 8.90% had someone living alone who was 65 years of age or older. The average household size was 2.49 and the average family size was 2.95.
In the county, the population was distributed as 22.50% under the age of 18, 19.80% from 18 to 24, 23.00% from 25 to 44, 21.50% from 45 to 64, and 13.20% who were 65 years of age or older. The median age was 32 years. For every 100 females, there were 102.80 males. For every 100 females age 18 and over, there were 102.20 males.
The median income for a household in the county was $33,849, and for a family was $40,465. Males had a median income of $32,127 versus $22,467 for females. The per capita income for the county was $16,372. About 9.60% of families and 16.10% of the population were below the poverty line, including 16.60% of those under age 18 and 7.60% of those age 65 or over.