Cass County is a county located in the western part of the U.S. state of Missouri and is part of the Kansas City metropolitan area. As of the 2010 census, the population was 99,478. Its county seat is Harrisonville. The county was organized in 1835 as Van Buren County, but was renamed in 1849 after U.S. Senator Lewis Cass of Michigan, who later became a presidential candidate.
According to the U.S. Census Bureau, the county has a total area of 702 square miles (1,820 km), of which 697 square miles (1,810 km) is land and 5.7 square miles (15 km) (0.8%) is water.
As of the census of 2000, there were 82,092 people, 30,168 households, and 22,988 families residing in the county. The population density was 117 people per square mile (45/km²). There were 31,677 housing units at an average density of 45 per square mile (18/km²). The racial makeup of the county was 95.62% White, 1.42% Black or African American, 0.58% Native American, 0.48% Asian, 0.04% Pacific Islander, 0.50% from other races, and 1.35% from two or more races. Approximately 2.21% of the population were Hispanic or Latino of any race.
There were 30,168 households out of which 38.10% had children under the age of 18 living with them, 63.60% were married couples living together, 9.10% had a female householder with no husband present, and 23.80% were non-families. 20.00% of all households were made up of individuals and 8.50% had someone living alone who was 65 years of age or older. The average household size was 2.69 and the average family size was 3.09.
In the county, the population was spread out with 28.40% under the age of 18, 7.30% from 18 to 24, 30.20% from 25 to 44, 22.30% from 45 to 64, and 11.70% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 95.90 males. For every 100 females age 18 and over, there were 92.90 males.
The median income for a household in the county was $49,562, and the median income for a family was $55,258. Males had a median income of $39,001 versus $26,174 for females. The per capita income for the county was $21,073. About 4.20% of families and 5.80% of the population were below the poverty line, including 7.00% of those under age 18 and 5.20% of those age 65 or over.