Fortifications

Fort O'Rourke (1862-1865) - A U.S. Civil War Fort first established as Redoubt C of Fort Lyon in 1862 in present day Alexandria, Fairfax County, Virginia. Named Fort O'Rourke in September 1863 after Colonel Patrick Henry O'Rourke, 104th New York Infantry, who was killed at Gettysburg on 2 Jul 1863.   

Established in 1862 as one of four redoubts in advance of Fort Lyon. After the battle at Gettysburg all four redoubts were were renamed for Union officers killed at that battle. The four newly created forts were Fort Weed, Fort Farnsworth, Fort O'Rourke and Fort Willard. Together with Fort Lyon these forts created a line across the southern approaches to the city of Alexandria.  

Fort O'Rourke (originally Redoubt C of Fort Lyon) was built by elements of the 34th Massachusetts Infantry. The original redoubt was built with a perimeter of 160 yards enclosing emplacements for 16 guns. Armament included one 24 pounder, two 8" howitzers, six 20 pounder Parrott rifles (2 vacant platforms).   Location:  Southeast corner of Fort Drive and Park Place in Alexandria, Fairfax County, Virginia.  ( Source - Fortwiki )