Smith County is a county located in the U.S. state of Tennessee. As of 2000, the population was 17,712. Its county seat is Carthage. It was created in 1799 and is named for Daniel Smith (surveyor), a Revolutionary War veteran who made the first map of Tennessee and served as a United States Senator.
Smith County is part of the Nashville-Davidson–Murfreesboro–Franklin Metropolitan Statistical Area.
According to the U.S. Census Bureau, the county has a total area of 325 square miles (840 km2), of which 314 square miles (810 km2) is land and 11 square miles (28 km2) (3.36%) is water.
As of the census of 2000, there were 17,712 people, 6,878 households, and 5,069 families residing in the county. The population density was 56 people per square mile (22/km²). There were 7,665 housing units at an average density of 24 per square mile (9/km²). The racial makeup of the county was 95.42% White, 2.53% Black or African American, 0.37% Native American, 0.17% Asian, 0.01% Pacific Islander, 0.59% from other races, and 0.93% from two or more races. 1.13% of the population were Hispanic or Latino of any race.
There were 6,878 households out of which 34.10% had children under the age of 18 living with them, 60.10% were married couples living together, 9.80% had a female householder with no husband present, and 26.30% were non-families. 23.40% of all households were made up of individuals and 11.10% had someone living alone who was 65 years of age or older. The average household size was 2.55 and the average family size was 3.00.
In the county, the population was spread out with 25.50% under the age of 18, 8.00% from 18 to 24, 30.00% from 25 to 44, 23.10% from 45 to 64, and 13.40% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 97.00 males. For every 100 females age 18 and over, there were 92.40 males.
The median income for a household in the county was $35,625, and the median income for a family was $41,645. Males had a median income of $30,853 versus $22,133 for females. The per capita income for the county was $17,473. About 10.30% of families and 12.20% of the population were below the poverty line, including 14.70% of those under age 18 and 14.80% of those age 65 or over.
Smith County was the site of a large saltpeter mine. Piper Cave, located near Monoville, contains the poorly-preserved remnants of dozens of saltpeter leaching vats. Most saltpeter mining in Middle Tennessee occurred during the War of 1812 and the Civil War, but the exact date of this operation is unclear. (Thomas C. Barr, Jr., “Caves of Tennessee”, Bulletin 64 of the Tennessee Division of Geology, 1961,568 pages.)