Rankin County is a county located in the U.S. state of Mississippi. The western border of the county is formed by the Pearl River. As of the 2010 census, the population was 141,617, making it the fourth-most populous county in Mississippi. The county seat is Brandon. The county is named in honor of Christopher Rankin, a Mississippi Congressman who served from 1819 to 1826.
According to the U.S. Census Bureau, the county has a total area of 806 square miles (2,090 km), of which 775 square miles (2,010 km) is land and 31 square miles (80 km) (3.8%) is water.
As of the census of 2000, there were 115,327 people, 42,089 households, and 31,145 families residing in the county. The population density was 149 people per square mile (57/km²). There were 45,070 housing units at an average density of 58 per square mile (22/km²). The racial makeup of the county was 81.03% White, 17.12% Black or African American, 0.16% Native American, 0.66% Asian, 0.02% Pacific Islander, 0.41% from other races, and 0.60% from two or more races. 1.32% of the population were Hispanic or Latino of any race.
According to the census of 2000, the largest ancestry groups in Rankin County were English 52.8%, Scots-Irish 15%, African 17.12%, Irish 5.1% and Scottish 3.2%.
There were 42,089 households out of which 36.70% had children under the age of 18 living with them, 58.10% were married couples living together, 12.20% had a female householder with no husband present, and 26.00% were non-families. 21.90% of all households were made up of individuals and 6.20% had someone living alone who was 65 years of age or older. The average household size was 2.62 and the average family size was 3.07.
In the county, the population was spread out with 25.90% under the age of 18, 9.10% from 18 to 24, 32.40% from 25 to 44, 23.00% from 45 to 64, and 9.50% who were 65 years of age or older. The median age was 35 years. For every 100 females, there were 95.60 males. For every 100 females age 18 and over, there were 92.50 males.
The median income for a household in the county was $44,946, and the median income for a family was $51,707. Males had a median income of $36,097 versus $26,096 for females. The per capita income for the county was $20,412. About 7.30% of families and 9.50% of the population were below the poverty line, including 12.20% of those under age 18 and 11.70% of those age 65 or over.
Rankin County has the second highest per capita income in the state of Mississippi.