Cumberland County is a county located in the U.S. state of Illinois. As of the 2010 census, the population was 11,048. Its county seat is Toledo.
According to the U.S. Census Bureau, the county has a total area of 347 square miles (900 km), of which 346 square miles (900 km) is land and 1.0 square mile (2.6 km) (0.3%) is water.
As of the 2010 United States Census, there were 11,048 people, 4,377 households, and 3,121 families residing in the county. The population density was 31.9 inhabitants per square mile (12.3/km). There were 4,874 housing units at an average density of 14.1 per square mile (5.4/km). The racial makeup of the county was 98.3% white, 0.3% black or African American, 0.2% Asian, 0.2% American Indian, 0.2% from other races, and 0.8% from two or more races. Those of Hispanic or Latino origin made up 0.7% of the population. In terms of ancestry, 30.6% were German, 17.4% were American, 11.7% were Irish, and 11.4% were English.
Of the 4,377 households, 31.3% had children under the age of 18 living with them, 57.7% were married couples living together, 8.6% had a female householder with no husband present, 28.7% were non-families, and 24.3% of all households were made up of individuals. The average household size was 2.50 and the average family size was 2.95. The median age was 40.9 years.
The median income for a household in the county was $42,101 and the median income for a family was $51,729. Males had a median income of $42,157 versus $29,142 for females. The per capita income for the county was $21,262. About 8.1% of families and 12.5% of the population were below the poverty line, including 19.4% of those under age 18 and 8.2% of those age 65 or over.