Grundy is a town in Buchanan County, Virginia, United States.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 is located at intersection of U.S. Route 460 and State Route 83 directly on the banks of the Levisa Fork River. Grundy is located in the coalfields of the Appalachian Mountains.According to the United States Census Bureau, the town has a total area of 5.0 square miles (13.1 Square Kilometer), all of it land.