In the 1830s Robert E. Lee, then a young 2nd Lieutenant in the U.S. Army who was working on Fort Monroe, was sent to Castle Calhoun to assess the situation. Lee found that the base of the island was spreading outward and ordered the existing base to be enlarged, temporarily halting further sinking of the fort.
During the American Civil War, Union forces were able to retain control over the fort despite the nearby presence of Confederate troops and the secession of Virginia from the Union. Soon an experimental cannon, “The Sawyer Gun,” was installed giving the Union garrison the ability to fire on Confederate batteries at Sewells Point in Norfolk, three miles away--an unusually long range for cannon of the era. The Sawyer also fired on the CSS Virginia in the Battle of the Ironclads at Hampton Roads. Less than three months later in May 1862, President Lincoln visited and personally ordered a shelling of Sewells Point before commencing plans to recapture Norfolk and Portsmouth.
Fort Calhoun was shortly thereafter renamed Fort Wool in honor of Maj. Gen John Ellis Wool, who is credited with Norfolk's capture. The original namesake, John C. Calhoun--once President Monroe's Secretary of War--had revealed himself to be a Confederate sympathizer and ardent secessionist.
After the war, Fort Wool remained relatively unfinished and unchanged until 1902 when it was found inadequate to withstand modern firepower. The fort was almost completely torn down and rebuilt to new standards. The facility was rearmed with modern artillery at this time, as the recent Spanish-American War had fueled fears of more conflict with European powers.
World War I necessitated more armament updates and submarine nets were installed between Fort Wool and Fort Monroe. World War II brought searchlights and radar towers. But the fort never again saw action, and the Army decommissioned the site in 1967, turning ownership over to the state of Virginia.
Fort Wool is now operated by the City of Hampton and offers tours during the summer months. The fort is an island, however, and can only be reached by boat. Private boats are welcome to dock at the fort during its normal operating hours. The privately operated Miss Hampton II Harbor Cruises stops at Fort Wool for a 30-minute guided tour.