Florence County, South Carolina  Florence County is a county located in the U.S. state of South Carolina. As of the 2010 census, its population was 136,885. Its county seat is Florence. Florence County is included in the Florence, SC Metropolitan Statistical Area. The county's population is about 60% urban. Florence County was formed from main sections of Darlington and Marion Counties plus other townships from Williamsburg and Clarendon Counties, starting in 1888. The last section of Williamsburg County was not added until 1921. Florence County was named for the daughter of General W. W. Harlee. According to the U.S. Census Bureau, the county has a total area of , of which is land and (0.5%) is water. At the 2000 census there were 125,761 people, 47,147 households, and 33,804 families living in the county. The population density was 157 people per square mile (61/km²). There were 51,836 housing units at an average density of 65 per square mile (25/km²). The racial makeup of the county was 58.65% White, 39.34% Black or African American, 0.22% Native American, 0.70% Asian, 0.02% Pacific Islander, 0.39% from other races, and 0.68% from two or more races. 1.10% of the population were Hispanic or Latino of any race. Of the 47,147 households 33.80% had children under the age of 18 living with them, 49.70% were married couples living together, 18.10% had a female householder with no husband present, and 28.30% were non-families. 24.50% of households were one person and 8.20% were one person aged 65 or older. The average household size was 2.59 and the average family size was 3.08. The age distribution was 25.90% under the age of 18, 9.70% from 18 to 24, 28.90% from 25 to 44, 23.60% from 45 to 64, and 11.80% 65 or older. The median age was 36 years. For every 100 females, there were 88.70 males. For every 100 females age 18 and over, there were 84.20 males. The median household income was $35,144 and the median family income was $41,274. Males had a median income of $32,065 versus $21,906 for females.