Charles Baring and Susan Heyward Baring built Mountain Lodge in 1827 as the community became known as the "Little Charleston of the Mountains" due to an influx of wealthy summer residents from the South Carolina Low Country. Historic Flat Rock Inc. bought the abandoned house and sold it in 2014 to Julien Smythe, a descendant of an owner of Connemara who along with wife Lori renovated the house. A post office called Flat Rock has been in operation since 1829. The village was named for granite rock formations which dotted the landscape. Historic Flat Rock Inc. began in 1968 after the loss of Ravenswood and began buying historic properties. A number of buildings in the village are included in the Flat Rock Historic District listed on the National Register of Historic Places. Also on the Register are Brookland and Carl Sandburg Home National Historic Site.
As of the census of 2000, there were 2,565 people, 1,169 households, and 937 families residing in the village. The population density was 327.1 people per square mile. There were 1,459 housing units at an average density of 186.0 per square mile. The racial makeup of the village was 98.83% White, 0.47% African American, 0.04% Native American, 0.12% Asian, 0.04% from other races, and 0.51% from two or more races. Hispanic or Latino of any race were 1.17% of the population. There were 1,169 households, out of which 15.3% had children under the age of 18 living with them, 76.5% were married couples living together, 1.8% had a female householder with no husband present, and 19.8% were non-families. 18.0% of all households were made up of individuals, and 10.9% had someone living alone who was 65 years of age or older. The average household size was 2.19 and the average family size was 2.46. In the village, the population was spread out, with 13.6% under the age of 18, 2.3% from 18 to 24, 13.4% from 25 to 44, 34.9% from 45 to 64, and 35.8% who were 65 years of age or older. The median age was 58 years. For every 100 females, there were 99.3 males. For every 100 females age 18 and over, there were 95.0 males. The median income for a household in the village was $67,813, and the median income for a family was $81,811. Males had a median income of $55,263 versus $34,375 for females. The per capita income for the village was $42,222. About 0.3% of families and 1.5% of the population were below the poverty line, including none of those under age 18 and 2.5% of those age 65 or over.
Carl Sandburg lived in the village from 1945 until his death in 1967. His home, once owned by Memminger, is part of the Carl Sandburg Home National Historic Site and a major tourist attraction in the village.
Buffalo Bob Smith, TV host of long-running children's program "Howdy Doody," retired to the Kenmure section of Flat Rock, yet sometimes used a Hendersonville address.
George A. Trenholm, a summer resident, was the second Secretary of the Treasury for the Confederacy from July 18, 1864, to April 27, 1865.