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4 Cities and towns
5 External links
The county was formed in 1855 from parts of Henderson County and Rutherford County. It was named for William Polk, a colonel in the American Revolutionary War.
According to the U.S. Census Bureau, the county has a total area of 618 km² (239 mi²). 616 km² (238 mi²) of it is land and 2 km² (1 mi²) of it is water. The total area is 0.31% water.
As of the census2 of 2000, there are 18,324 people, 7,908 households, and 5,337 families residing in the county. The population density is 30/km² (77/mi²). There are 9,192 housing units at an average density of 15/km² (39/mi²). The racial makeup of the county is 92.26% White, 5.89% Black or African American, 0.19% Native American, 0.24% Asian, 0.03% Pacific Islander, 0.63% from other races, and 0.76% from two or more races. 3.01% of the population are Hispanic or Latino of any race.
There are 7,908 households out of which 23.50% have children under the age of 18 living with them, 56.30% are married couples living together, 7.90% have a female householder with no husband present, and 32.50% are non-families. 28.90% of all households are made up of individuals and 15.00% have someone living alone who is 65 years of age or older. The average household size is 2.28 and the average family size is 2.78.
In the county the population is spread out with 20.10% under the age of 18, 5.80% from 18 to 24, 24.20% from 25 to 44, 26.30% from 45 to 64, and 23.60% who are 65 years of age or older. The median age is 45 years. For every 100 females there are 90.20 males. For every 100 females age 18 and over, there are 87.10 males.
The median income for a household in the county is $36,259, and the median income for a family is $45,096. Males have a median income of $29,375 versus $23,070 for females. The per capita income for the county is $19,804. 10.10% of the population and 6.40% of families are below the poverty line. Out of the total people living in poverty, 11.70% are under the age of 18 and 8.80% are 65 or older.