According to the U.S. Census Bureau, the county has a total area of, of which is land and is water. The county straddles the western edge of the Cumberland Plateau, with the eastern portion of the county lying atop the Plateau, and the western portion lying on the lower Highland Rim. The Caney Fork, the county's primary drainage, forms part of its northern border with White County. The Rocky River, a tributary of the Caney Fork, forms part of the county's western border with Warren. Cane Creek, another tributary of the Caney Fork, drains the Fall Creek Falls area. Big Bone Cave is located in the northwest corner of Van Buren County. It is one of the best-known and most historic caverns in Tennessee. It was mined by prehistoric Indians for gypsum and salts and was the site of the largest saltpeter mine in Tennessee during the War of 1812 and again during the American Civil War. The cave is named for the discovery of the skeleton of a Giant Ground Sloth by saltpeter miners in 1811. Many of the wooden saltpeter mining artifacts in the cave remain in a remarkable state of preservation, due to the extreme dryness of the cave. Van Buren County boasts over 850 documented caves, making it one of the most cave dense regions in the world.
As of the 2010 census, there were 5,548 people and 2,096 households in the county. The population density was 20.3 people per square mile. There were 2,673 housing units at an average density of 9.8 per square mile. The racial makeup of the county was 97.5% White, 0.7% Black or African American, 0.3% Native American, 0.2% Asian, and 0.9% from two or more races. 0.9% of the population were Hispanic or Latino of any race. There were 2,096 households out of which 29.3% had children under the age of 18 living with them, 54.9% were married couplesliving together, 11.7% had a female householder with no husband present, and 28.0% were non-families. 24.3% of all households were made up of individuals, while 30.6% had someone living alone who was 65 years of age or older. The average household size was 2.43. 82.6% of occupied housing units were owner-occupied, meaning that 17.4% were renter-occupied. In the county, the population was spread out with 23.2% up to the age of 19, 8.8% from 20 to 29, 12.4% from 30 to 39, 13.4% from 40 to 49, 16.8% from 50 to 59, 14.7% from 60 to 69, and 10.7% who were 70 years of age or older. The median age was 44.5 years. Women make up 50.2% of the population. The median income for a household in the county was $29,087. The per capita income for the county was $17,160. 24.6% of the population were below the poverty line.
