Fort Pulaski National Monument Fort Pulaski National Monument is located between Savannah and Tybee Island , Georgia . It preserves Fort Pulaski , where in 1862 during the American Civil War , the Union Army successfully tested a rifled cannon , the success of which rendered brick fortifications obsolete . The fort was also used as a prisoner - of - war camp . The National Monument includes most of Cockspur Island ( containing the fort ) and all of adjacent McQueens Island . Construction . Following the War of 1812 , U . S . President James Madison ordered a new system of coastal fortifications to protect the United States against foreign invasion . Construction of a fort to protect the port of Savannah began in 1829 under the direction of Major General Babcock , and later Second Lieutenant Robert E . Lee , a recent graduate of West Point . The new fort would be located on Cockspur Island at the mouth of the Savannah River . In 1833 , the facility was named Fort Pulaski in honor of Kazimierz Pulaski , a Polish soldier and military commander who fought in the American Revolution under the command of George Washington . Pulaski was a noted cavalry man and played a large role in training Revolutionary troops . He took part in the sieges of Charleston and of Savannah . Fort Pulaski belonged to what is known as the Third System of coastal fortifications , which were characterized by greater structural durability than the earlier works . Most of the nearly thirty Third System forts built after 1816 still exist along either the Atlantic or Gulf coasts . Wooden pilings were sunk up to into the mud to support an estimated 25 , 000 , 000 bricks . Fort Pulaski was finally completed in 1847 following eighteen years of construction and nearly $ 1 million in construction costs . Walls were eleven feet thick , thought to be impenetrable except by only the largest land artillery - which at the time were smooth bore cannon . These cannons had a range of only around a half mile , and the nearest land ( Tybee island ) was much further away than that . It was assumed that the Fort would be invincible to enemy attack . LT Lee remarked that " one might as well bombard the Rocky Mountains as Fort Pulaski " . Civil War . Though completed in 1847 , Fort Pulaski was under the control of only two caretakers until 1860 when South Carolina seceded from the United States and set in motion the Civil War . It was at this time that Georgia governor Joseph E . Brown ordered Fort Pulaski to be taken by the state of Georgia . A steamship carrying 110 men from Savannah traveled downriver and the fort was seized by the state of Georgia . Following the secession of Georgia in February 1861 , the state joined the Confederate States of America . Confederate troops then moved into the fort . By December 1861 , Tybee Island was thought to be too isolated and unprepared for conflict and was abandoned by Confederate forces . This allowed Union troops to gain a foothold across the Savannah River from Fort Pulaski . Union forces under Quincy A . Gillmore began construction of batteries along the beaches of Tybee . Siege and reduction of Fort Pulaski . On the morning of April 10 , 1862 Union forces asked for the surrender of the Fort to prevent needless loss of life . Colonel Charles H . Olmstead , commander of the Confederate garrison , rejected the offer . Fort Pulaski was prepared for a possible infantry attack . However , it never endured a direct land assault . Using 36 guns , including the new James Rifled Cannon and Parrott rifles , Union troops began the long sustained bombardment of Fort Pulaski . The rifled projectiles could be accurately fired farther ( 4 – 5 miles ) than the larger and heavier smoothbore cannonballs . Within 30 hours , the new rifled cannon had breached one of the fort ' s corner walls . Shells now passed through the fort dangerously close to the main powder magazine . Reluctantly , Colonel Olmstead surrendered the fort . Only two soldiers , one Confederate and one Union , were injured in the attack . Olmsted ' s decision to surrender haunted him for decades . We were absolutely isolated beyond any possibility of help from the Confederate authorities , and I did not feel warranted in exposing the garrison to the hazard of the blowing up of our main magazine - - a danger which had just been proved well within the limits of probability . . . . There are times when a soldier must hold his position to the last extremity , which means extermination , but this was not one of them . . . . That the fort could and would be absolutely destroyed by the force of the enemy was a demonstrated fact , . . . while our own power to harm them had been reduced to a minimum , . . . I am still convinced that there was nothing else that could be done . Gillmore succeeded almost entirely because of his rifled cannon , which caused massive damage in the walls of the fort . Gillmore ' s triumph won him promotion from engineer captain to brigadier general . Union Control . Within six weeks of the surrender , Union forces repaired the Fort and all shipping in and out of Savannah ceased . The loss of Savannah as a viable Confederate port crippled the Southern war effort . With the Fort securely in Union control , General David Hunter , commander of the Union garrison issued General Order Number Eleven , which stated that all slaves in Florida , Georgia , and South Carolina were now free . President Abraham Lincoln quickly rescinded the order , but later issued his own Emancipation Proclamation in 1863 . At this time , Fort Pulaski was made a final destination on the Underground Railroad as slaves throughout the area were freed upon arrival on Cockspur Island . The garrison of Union soldiers reached 600 during the initial occupation , but as the War dragged on it became obvious the Southern forces would not be able to retake the fort . The garrison was later reduced to about 250 . Late in the war , the fort was turned into a prison for a group of captured Confederate officers known as " The Immortal Six Hundred . " Thirteen of these men would die at the fort . After the war ended , Fort Pulaski continued as a military and political prison for a short while . It would house a Confederate Secretary of State , Secretary of the Treasury , Secretary of War , Assistant Secretary of War as well as three state governors , a senator and the men who had commanded the fort after it had been taken by the South . Post war . Between 1869 and 1872 the demilune to the rear of the Fort was covered with powder magazines and the few gun positions left were enlarged for heavier guns . By the turn of the 20th century , the fort began to fall into disrepair . In an effort to save the old fort , the War Department finally declared Fort Pulaski a National Monument on October 15 , 1924 by presidential proclamation of Calvin Coolidge . The monument was transferred from the War Department to the National Park Service on August 10 , 1933 . At that time repairs were started , when members of the Civilian Conservation Corps arrived on Cockspur Island and began rehabilitation of the fort . Fort Pulaski was opened to the public only for a short time before the beginning of World War II . This war would see further use of Cockspur Island as a section base for the U . S . Navy . Following World War II , Fort Pulaski reverted to the Park Service ' s control , and it was administratively listed on the National Register of Historic Places on October 15 , 1966 . Fort Pulaski remains open to the public , with a museum opened in the 1980s . In November 2009 , Fort Pulaski was used in the filming of Robert Redford ' s movie " The Conspirator " , based on the conspiracy involving the assassination of President Abraham Lincoln , most notably as the site for the gallows used to hang Mary Surratt and others . It was used once again in filming the 2012 horror film " Abraham Lincoln vs . Zombies " . It was chosen for location shooting of scenes where Lincoln confronts zombies who had overrun a Confederate stronghold .