Grundy is a town in Buchanan County, Virginia, United States. The population was 1,105 at the 2000 census. It is the county seat of Buchanan County. The town is noted for its educational institutions and their role in the town's economic rebirth. In the past, the town served as a stopover for Union troops on their way to the Battle of Saltville. The town is also noteworthy for its flood control project, where the mountain across the river was blasted to make way for new development.
The town, founded in 1858 upon the formation of Buchanan County, was named for Felix Grundy (1777–1840), United States Attorney General (1838–1839) and United States Senator from Tennessee (1839–1840). It was incorporated in 1876. The present courthouse dates from 1905.
In October 1864, Union raiders under Brigadier General Stephen G. Burbridge passed through Grundy on their way to destroy the saltworks near Saltville in Smyth County, where they were met by Confederate troops commanded by Brigadier General Alfred E. Jackson at the Battle of Saltville. The Union troops were defeated in the battle, but returned later and succeeded in destroying the saltworks.