Ogemaw County is a county located in the U.S. state of Michigan. As of the 2010 census, the population was 21,699. The county seat is West Branch.
According to the U.S. Census Bureau, the county has a total area of 575 square miles (1,490 km), of which 563 square miles (1,460 km) is land and 11 square miles (28 km) (2.0%) is water. Ogemaw County is considered to be part of Northern Michigan.
As of the 2000 United States Census, there were 21,645 people, 8,842 households, and 6,189 families residing in the county. The population density was 38 people per square mile (15/km²). There were 15,404 housing units at an average density of 27 per square mile (11/km²). The racial makeup of the county was 97.48% White, 0.13% Black or African American, 0.60% Native American, 0.38% Asian, 0.03% Pacific Islander, 0.13% from other races, and 1.25% from two or more races. 1.16% of the population were Hispanic or Latino of any race. 28.7% were of German, 12.3% American, 10.2% English, 9.2% Irish, 7.0% French and 6.7% Polish ancestry. 97.9% spoke only English at home.
There were 8,842 households out of which 27.10% had children under the age of 18 living with them, 57.40% were married couples living together, 8.80% had a female householder with no husband present, and 30.00% were non-families. 25.70% of all households were made up of individuals and 12.20% had someone living alone who was 65 years of age or older. The average household size was 2.41 and the average family size was 2.87.
The county population contained 23.50% under the age of 18, 6.40% from 18 to 24, 24.40% from 25 to 44, 27.00% from 45 to 64, and 18.80% who were 65 years of age or older. The median age was 42 years. For every 100 females there were 98.40 males. For every 100 females age 18 and over, there were 95.50 males.
The median income for a household in the county was $30,474, and the median income for a family was $34,988. Males had a median income of $31,003 versus $20,544 for females. The per capita income for the county was $15,768. About 11.00% of families and 14.00% of the population were below the poverty line, including 18.50% of those under age 18 and 9.90% of those age 65 or over.