This padlock faceplate was discovered in a layer of cellar fill adjacent to the brick foundation of what was likely a domestic structure at the Old Colchester Park and Preserve. Cellar fill is material that accumulates after a structure is no longer used for its intended purpose. Though the faceplate is fragmented and heavily oxidized, it is still possible to make out remnants of the inner locking mechanism, and the distinctive keyhole shape is still visible. Padlocks such as these were commonly used in the 18th century. They would likely have been heart-shaped and opened with a key. This particular one may have been used on a door or to secure belongings in a trunk.
See information about other artifacts and current excavations in Fairfax County at cartarchaeology.wordpress.com.