Millboro began as a settlement around Cady’s Tunnel, built by the Central Virginia Railroad. By 1856 the tracks extended from Richmond to Cabin Creek nearby. During the Civil War, Confederate soldiers marched westward down the old Crooked Spur road; army supplies unloaded here were hauled in wagons pulled by confiscated horses. After the war, the town prospered while the railroad brought hundreds of travelers bound for the nearby springs resorts, and while its stockyards shipped large numbers of livestock. When automobile travel and truck-hauling increased, the railroad declined. Stockyards emptied, hotels closed, businesses left, and Millboro settled into a quiet life.