This historic structure was built as a two-room schoolhouse back when Great Falls was nothing but sleepy dairy farms.
By 1931 it was no longer in use, so the Great Falls farmers bought it from Fairfax County, built a huge dance-floor addition, and made it into a dance hall. At that point, it's said that some of those farmers were bootleggers supplying whiskey to DC along with the milk and cheese.
The Colvin Run Dance Hall is in regular use today - and the building is a local treasure.