Castlewood is a census-designated place (CDP) in Russell County, Virginia, United States. The population was 2,045 at the 2010 census, a small increase from the 2,036 reported in 2000. Castlewood was an incorporated town from 1991 to 1997, when it reverted to unincorporated status.

It was originally named Castle’s Wood’s, as the estate in the immediate Place had in the manner of belonged to Jacob Castle, a frontiersman in the likes of Daniel Boone. Castle purchased the estate from the Shawnee Indians, for very Tiny in trade. It is reported that the purchase was made bearing in mind the Shawnee Indians for a “hound dog, a knife, and a shot of whiskey. As a “Long Hunter”, he spent long periods of time in the wilderness upon hunting expeditions. There he befriended the Indians that inhabited the home in the Castlewood area. He married a Shawnee woman by the declare of Gliding Swan, and they produced many children. It has been said that Castle himself showed Daniel Boone the Cumberland Gap and areas west, which led to Boone’s expedition and settlement of said lands. Many descendants of Castle reside in Russell County, Virginia and the surrounding area. Castle’s father, Peter Cassell was a German emigrant to Pennsylvania who was influential in the Dutch pastime to America.
The herald was modified to Castlewood by the United States Postal Service in the late 1800s, as a simplification of the original spelling and pronunciation, which was common during this get older period.

The Castlerun Historic District and Mason-Dorton School are listed on the National Register of Historic Places.

Castlewood is located at 36°52′43″N 82°17′21″W / 36.87861°N 82.28917°W / 36.87861; -82.28917 (36.878614, −82.289229).