Tradition holds that this barn was constructed in 1701 by Major Arthur Allen II. It is the oldest surviving outbuilding at Bacon's Castle and one of the oldest in Virginia. An inventory of Major Allen's belongings taken at the time of his death in 1711 indicates that the property was extensively farmed then, and the barn would have been in frequent use. Its partially exposed structural system shows how beams were joined to create a strong frame without extensive use of nails. Before mechanized tools were invented, beams were shaped by hand with a saw or an adze, leaving smoothed surfaces with slight peaks and depressions.