A developer erected this monument in a housing area off Brooke Road (Sentinel Ridge). It reads: Established on this spot in February of 1863, by New York troops of the 12th Corps, 2nd Division, Army of the Potomac, Redoubt #3 was manned by up to 100 soldiers and supported by 4 rifled artillery pieces. It guarded the approaches to the Union Supply Depot at nearby Aquia Landing and the 12th Corps camps on the hills to the East during the winter of 1862-1863. Redoubt #3 was a square enclosure approximately 70' long and 12' high.