| 1813 | -State of Delaware deeds island to U.S. government |
| 1815 | -First earthwork fortification built |
| 1819 | -Construction of masonry fort begun |
| 1823 | -Fort completed |
| 1831 | -Fire destroys most of fort |
| 1833 | -Rest of fort demolished, plans laid to rebuild |
| 1839 | -Operations halted over land ownership lawsuit filed by a Dr. Gale, of NJ |
| 1847 | -Congress appropriates $1 million for new fort, lawsuit on-going |
| 1848 | -Arbitrator rules in favor of original Delaware ownership, construction begun |
| 1851 | -Foundations completed. Setting of pilings takes entire $1 million and further work suspended until study made as to cost-feasibility of completing fort. |
| 1854 | -Congress decides to spend another $1 million and work begun again |
| 1856 | -Secretary of State Jefferson Davis advises Senate that the project will cost another $750,000 if fort is to be finished by 1859. Congress approves the appropriation. |
| 1859 | -Fort completed at a total cost of nearly $3 million |
| 1860 | -One company of Marines occupies the fort |
| 1861 | -After Confederates fire on Fort Sumter, the Commonwealth Artillery of Pennsylvania moves into fort |
| April | After Battle of Kernstown, VA, 250 Confederate prisoners arrive at fort |
| May | -20 32-pounder Columbiad and 20 howitzer cannon arrive and installed |
| June | -Commissary General of Prisons inspects and orders enough barracks for 2,000 prisoners to be built |
| July 16 | -Prisoners escape at night |
| July 19 | -200 prisoners make night escape. Guard boat sent to patrol around island. |
| October | -Colnel Delvin D. Perkins becomes Commanding Officer of fort |
| 1863 |
| January 17 |
-British Consul sends letter of protest to U.S. Secretary of State Seward regarding harsh conditions of British prisoners who had been captured while trying to run Union naval blockade and sent to fort |
| April 25 | -Brigadier General Albin A. Shoepf becomes Commanding Officer of fort |
| 1864 |
| Summer | -60 Confederate officers, including 7 generals, are sent to be held prisoner under Confederate guns in Charleston Harbor and near Fort Wagner, SC, in retaliation for similar actions by Confederates with Union prisoners. Soon, number increased to 600 Confederate prisoners. Group forever known as "the Immortal Six-Hundred". |
| June | -8,000 prisoners on island |
| July 13 | -Confederate Exchange Agent Robert Ould sends letter of protest to his Union counterpart over the conditions and treatment of prisoners |
| October | -Prison population drops to 6,498 and never goes higher than 9,318 again |
| -Smallpox epidemic strikes. Will eventually kill over 200 prisoners and guards. |
| 1865 |
| April 4 | -100-gun salute fired to celebrate fall of Richmond |
| 1866 |
| January | -Last prisoner, Burton S. Harrison, Jefferson Davis' personal secretary, released. General Shoepf mustered out, goes to work for U.S. Patent Office. |
| 1870 | -Garrison withdrawn, small caretaker force remains |
| 1896 | -Congress appropriates $600,000 to install 3 16-inch disappearing guns in south end of fort |
| 1898 | -16-inch guns installed; several 3-inch batteries placed around island |
| 1903 | -Garrison, minus small caretaker force, is again removed |
| 1917 | -Fort garrisoned during WWI |
| 1919 | -All troops, less 100, removed |
| 1941 | -December 7th, a company is sent to the fort |
| 1943 | -Disappearing guns removed |
| 1944 | -Fort abandoned |
| 1945 | -Island declared surplus property |
| 1947 | -Island transferred to State of Delaware |
| 1951 | -Established as State Park |
