Pettis County is a county located in west central U.S. state of Missouri. As of the 2010 census, the population was 42,201. Its county seat is Sedalia. The county was organized January 24, 1833, and named after former U.S. Representative Spencer Darwin Pettis.
According to the U.S. Census Bureau, the county has a total area of 686 square miles (1,780 km), of which 682 square miles (1,770 km) is land and 4.0 square miles (10 km) (0.6%) is water. It is drained by Lamine River and branches.
As of the census of 2000, there were 39,403 people, 15,568 households, and 10,570 families residing in the county. The population density was 58 people per square mile (22/km²). There were 16,963 housing units at an average density of 25 per square mile (10/km²). The racial makeup of the county was 92.06% White, 3.04% Black or African American, 0.38% Native American, 0.39% Asian, 0.05% Pacific Islander, 2.46% from other races, and 1.62% from two or more races. Approximately 3.88% of the population were Hispanic or Latino of any race.
There were 15,568 households out of which 32.50% had children under the age of 18 living with them, 53.30% were married couples living together, 10.50% had a female householder with no husband present, and 32.10% were non-families. 27.00% of all households were made up of individuals and 11.70% 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 3.01.
In the county, the population was spread out with 26.30% under the age of 18, 9.30% from 18 to 24, 27.90% from 25 to 44, 21.10% from 45 to 64, and 15.40% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 94.40 males. For every 100 females age 18 and over, there were 91.70 males.
The median income for a household in the county was $31,822, and the median income for a family was $38,073. Males had a median income of $29,221 versus $19,554 for females. The per capita income for the county was $16,251. About 10.20% of families and 12.80% of the population were below the poverty line, including 16.60% of those under age 18 and 10.50% of those age 65 or over.
Pettis County Missouri neighborhoods include: Cambridge Village, Chapel Woods, Country Estates, Crown Hill, E 16th St, Heck Ave, Liberty Park, Maplewood/Riverview, Southgate Loop, South Sedalia, Southwest Village, Thompson – Limit