Dahlgren Hall, designed by architect Ernest Flagg in 1898, was completed in 1903. It was named for Rear Admiral John A. Dahlgren, U. S. Navy, a Civil War inventor of scientifically designed, large-caliber naval guns. Dahlgren Hall has served variously as an armory, indoor drill area and a Weapons Department laboratory. In 1975 Dahlgren Hall was renovated to include a recreational indoor skating rink and the Drydock Restaurant.