Forts seem to be significant structures in many nations, constructed to defend certain travel routes or to protect nearby cities and towns. According to the American Battlefield Trust, forts often dictated the military strategy of both sides. These strongholds were built even before the United States was developed as a nation and encapsulated the history of the country as it began to develop.
The first constructed fortress was Castillo de San Marcos in St. Augustine, Florida, built between 1672 and 1695 and one of several pre-Civil War forts erected around major coastal cities to guard against foreign invasion. This fortification continued following the War of 1812, which had revealed vulnerabilities, and was already underway when the Civil War erupted with the 1861 Confederate attack on Fort Sumter. (These are the oldest military forts built before America was a country.)
The impending Civil War accelerated the additional need to fortify areas around vital cities, supply lines, and transit routes. Over 60 forts were built around Washington D.C. alone, as nearby states seceded or harbored Confederate sympathies. Traditionally, brick or masonry forts were standard. However, new rifled cannons made those obsolete, prompting inexpensive, rapidly-built earthwork forts better suited to withstand cannonballs. (Forts have now become outdated, with attacks conducted by air, like the Iranian-backed Houthi rebels who threaten to strike Saudi Arabia.)
While many forts perished during or after the war, some still stand today. To identify historic Civil War forts still standing that you can explore, 24/7 Tempo compiled military sites used then per the National Park Service, and state and regional tourism agencies. We focused on locations that are accessible to the public that have preserved original structures, ruins, or reconstructions. Some also feature museums and battle reenactments on their grounds.
Though not a comprehensive list, these sites include both masonry and earthworks forts, some predating the war and others hastily built during it. Many remained in military use in later wars with updated fortifications, while others were abandoned and later recovered. Most are now part of state or national parks commemorating this history. (These were the largest battles of the Civil War.)
Here are historic Civil War forts still standing that you can explore.
Fort Mifflin
- Location: Philadelphia, Pennsylvania
- Constructed: 1771
The site of a Revolutionary War siege and later a Civil War prison, Fort Mifflin (also known as Mud Island) is a National Historic Landmark with educational programming and visiting hours from March 1 through December 15. Part of the fort’s grounds are still in use by the Army Corps of Engineers, making it the oldest military fort in use in the U.S.
Fort Moultrie
- Location: Sullivan’s Island, South Carolina
- Constructed: 1776
Fort Moultrie was abandoned by Federal troops shortly after South Carolina seceded from the Union. It was taken over by the Confederates and, along with the better-known nearby Fort Sumter, heavily bombarded by Union fleets. Many of the fort’s buildings have been restored and are now part of a National Historic Park.
Fort Trumbull
- Location: New London, Connecticut
- Constructed: 1777
Used as a training center for Union troops, Fort Trumbull has been through multiple upgrades and rebuilds. The current masonry fort was built between 1839 and 1852 and is open to the public as part of a Connecticut State Park that offers tours and interactive exhibits.
Fort Jay
- Location: Governor’s Island, New York
- Constructed: 1794
Built to defend upper New York Bay, Fort Jay was used to house Confederate officer prisoners of war. Several Rodman guns – Civil War-era cannons – remain on site, and the well-preserved star-shaped fort lies protected within the Governor’s Island National Monument, whose grounds visitors can tour on weekends.
Fort Washington
- Location: Fort Washington, Maryland
- Constructed: 1808
Intended to defend Washington, D.C. from river approaches, Fort Washington was garrisoned by U.S. Marines during the Civil War. The current masonry structure, built in 1824, along with concrete artillery batteries built in the 1890s, is contained within the grounds of Fort Washington National Park and is open to the public daily.
Fort Delaware
- Location: Pea Patch Island, Delaware
- Constructed: 1817
Used as a prison for Confederate prisoners of war, Fort Delaware housed nearly 33,000 men during the conflict. It is now part of a living history museum where staff dressed in period clothing perform demonstrations. The pentagonal fort, surrounded by a moat, is located on an island accessible by a seasonal ferry.
Fort Gaines
- Location: Dauphin Island, Alabama
- Constructed: 1821
During the Battle of Mobile Bay, Fort Gaines saw extensive fighting in which Union naval forces defeated the Confederate fleet and secured the bay. One of the best preserved Civil War masonry forts, the site features original tunnels, cannons, a blacksmith shop, and pre-Civil War buildings. However, storms and shore erosion threaten the future of the site.
Fort Jackson
- Location: Buras, Louisiana
- Constructed: 1822
This star-shaped masonry fort was built to defend New Orleans. In 1862, it was besieged for 12 days and hit with several thousand cannon shots until Union forces were able to advance past it and capture New Orleans. Afterward, it served as a Union prison. Due to damage from Hurricane Katrina in 2005, the current fort’s interior is closed to the public but the grounds and exterior are accessible and the nearby Fort Jackson Museum contains historical artifacts and exhibits.
Fort Pulaski
- Location: Cockspur Island, Georgia
- Constructed: 1829
Built between 1829 and 1847 for the defense of Savannah, Fort Pulaski was seized by Confederate troops in 1860. In 1862, Union forces utilized new artillery technology to bombard the fort, causing massive damage and leading the Confederate colonel in charge to surrender. The pentagonal fort is now a national monument revealing some of the original artillery damage.
Fort Sumter
- Location: Charleston, South Carolina
- Constructed: 1829
The construction of Fort Sumter was initiated in 1829 but was incomplete when the South Carolina militia began bombarding it in 1861, which was the beginning of the Civil War. It was heavily damaged by Union artillery during the Siege of Charleston Harbor and reduced to a heap of rubble. After the war, the walls were partially rebuilt and now the fort is part of the Fort Sumter and Fort Moultrie National Historic Park, accessible by ferry.
Fort Independence
- Location: Castle Island, Massachusetts
- Constructed: 1833
Formerly known as Castle William, this fort sits in a defensive position in Boston Harbor. Although the site has been fortified since 1634, the current buildings date from 1833 to 1851 and were used to train Union soldiers. Fort Independence is now a popular State Park, offering visitors free tours during the summer.
Fort Warren
- Location: Georges Island, Massachusetts
- Constructed: 1833
Located near the mouth of Boston Harbor, Fort Warren is a star-shaped stone and granite fort built between 1833 and 1861. It served as a prison for Confederate officers and other political prisoners and was in active military use until 1947. The impressive military base and a conjoined museum are accessible by ferry or private boat as a part of the Boston Harbor Islands National Recreation Area.
Fort Schuyler
- Location: Bronx, New York
- Constructed: 1833
Constructed to protect New York City’s eastern waterways, Fort Schuyler was garrisoned in 1861 and was used as a prison, hospital, and training center during the war. Abandoned in the 1920s, the fort later became the site of the New York State Merchant Marine Academy. The restored fort remains a school to this day and also contains a maritime museum.
Fort Morgan
- Location: Gulf Shores, Alabama
- Constructed: 1834
This pentagonal bastion fort was captured by Confederates days before Alabama seceded from the Union and was used extensively during the war to protect merchant ships evading a blockade at Mobile Bay before it fell into Union hands. The fort has sustained hurricane damage in recent years but is open daily for tours.
Fort Pickens
- Location: Santa Rosa Island, Florida
- Constructed: 1834
One of the very few Southern fortifications that were occupied by the Union during the entirety of the Civil War, Fort Pickens faced multiple battles and bombardments. It was updated during both world wars and, along with a military museum, is now a part of the Gulf Islands National Seashore, open to visitors.
Fort Barrancas
- Location: Pensacola, Florida
- Constructed: 1839
Months before the start of the Civil War, U.S. troops stationed at Fort Barrancas abandoned the post and moved just across the water to the more easily defendable Fort Pickens. Fort Barrancas was then briefly garrisoned by Confederate forces before it was again abandoned in May of 1862. The well-preserved buildings and visitors center are located on the Naval Air Station Pensacola.
Fort Zachary Taylor
- Location: Key West, Florida
- Constructed: 1845
At the southwest tip of Key West, Fort Zachary Taylor was held by the Union during the Civil War and used to launch offensives on blockade-running merchant ships. The fort was used extensively in subsequent wars and is now a state park and National Historic Monument that features a large cache of weapons and hosts Civil War reenactments.
Fort Jefferson
- Location: Garden Key, Florida
- Constructed: 1846
Although it was never finished, this fort in the lower Florida Keys is a massive structure covering 16 acres. It was garrisoned by Federal forces during the Civil War and used as a prison, largely for Union deserters. The impressive remains are a part of Dry Tortugas National Park, which is accessible by ferry, boat, or seaplane.
Fort Clinch
- Location: Amelia Island, Florida
- Constructed: 1847
Seized by Confederates in 1861, this fort northeast of Jacksonville was used as a base for blockade-running ships before it was abandoned and re-taken by Federal troops. During the Great Depression, the Civilian Conservation Corps restored the fort to its Civil War-era condition and Fort Clinch State Park opened in 1938. Currently, living history demonstrations and reenactments draw visitors to the park.
Fort Tompkins
- Location: Staten Island, New York
- Constructed: 1847
Built to guard New York City against land approaches from the west, this fort on Staten Island was used to house and train soldiers during the Civil War but never saw battle. It remains intact and is currently part of the Fort Wadsworth National Recreation Area. Visitors can no longer enter the fort, but the grounds offer views of the historic structures and many batteries remain open.
Fort Massachusetts
- Location: Ship Island, Mississippi
- Constructed: 1859
Located on a Gulf Coast island, this fort was seized by Mississippi militia members in January 1861 but eventually abandoned. Union forces then took over the island and stationed troops there who would go on to capture New Orleans. Due to the harsh environment, many soldiers died while stationed at Fort Massachusetts.
Now maintained as part of the Gulf Islands National Seashore, the fort is accessible by ferry and tours run from spring to fall.
Fort Popham
- Location: Phippsburg, Maine
- Constructed: 1861
This granite fort at the mouth of the Kennebeck River was constructed to protect Augusta from a possible Confederate invasion. The fort was never completed, as new weapons technology, namely the rifled cannon, propelled masonry forts into obsolescence. Now a State Historic Site, Fort Popham is a popular area with tourists and photographers.
Fort Ward
- Location: Alexandria, Virginia
- Constructed: 1861
One of many forts built to defend Washington, D.C., Fort Ward never saw battle and was eventually abandoned and deconstructed; however, its earthworks remained intact for over a century. In 1962, the city of Alexandria began an archaeological restoration that rebuilt the northwest bastion. The fort grounds now feature replicated cannons, reenactments, and a Civil War museum.
Fort Rodman
- Location: New Bedford, Massachusetts
- Constructed: 1861
Although construction of the fort began in 1857, by the time of the Civil War, it was nowhere near completion, and a nearby earthwork fort (Fort Taber) was built in the meantime. The fort complex never saw battle. The area is currently open to the public as Fort Taber Park, but the structure at Fort Rodman is awaiting renovation before the interior is open to the public. A military museum on-site offers exhibits and reenactments.
Fort Totten
- Location: Queens, New York
- Constructed: 1862
Located at the head of Little Neck Bay, this fort was designed in part by Robert E. Lee. The original plans were never completed, but subsequent wars saw many additions to the fortifications. Fort Totten is currently a park maintained by the New York City Department of Parks & Recreation, where visitors can tour the fortress and other historic buildings.
Fort Negley
- Location: Nashville, Tennessee
- Constructed: 1862
Constructed largely by runaway slaves who flocked to Nashville after Union forces took over the city, Fort Negley never ended up seeing battle and was abandoned after the war. Significant ruins of the fort have been restored and a visitors center offers educational programming. During archaeological analysis, unmarked graves thought to be those of buried slave laborers were uncovered on the grounds, halting the planned redevelopment of a vacant on-site stadium.
Fort Donelson
- Location: Dover, Tennessee
- Constructed: 1862
Soon after it was built by Confederate forces in 1862, Fort Donelson was captured by the Union Army under General Ulysses S. Grant and remained in the Union’s power for the remainder of the war. It is now a part of Fort Donelson National Battlefield Park, which contains both ruins and rebuilt areas and includes the nearby Fort Heiman.
Fort Pocahontas
- Location: Charles City, Virginia
- Constructed: 1864
The site of the Battle of Wilson’s Wharf, a skirmish between the Army of Northern Virginia and the 1st and 10th U.S. Colored Troops (USCT) – regiments of mainly African-American soldiers – this fort site contains intact earthworks built by the USCT. Fort Pocahontas became a refuge for runaway slaves until its abandonment in 1865. The site is now on the National Register of Historic Places and offers occasional historical reenactments.
Fort Monroe
- Location: Hampton, Virginia
- Constructed: 1819
Fort Monroe was constructed to protect the Chesapeake Bay after the War of 1812 and is the largest fort by area ever built in the United States. Confederate president Jefferson Davis was imprisoned there for two years beginning in May 1865. The fort remained in active use until 2011 when portions of the grounds were declared a national monument.
Fort McHenry
- Location: Baltimore, Maryland
- Constructed: 1798
Built to protect Baltimore Harbor, Fort McHenry saw continuous use until World War I. During the Civil War, it housed Confederate soldier prisoners of war, as well as Confederate sympathizers. The grounds were made a National Park in 1925, and the fort is now a National Historic Monument open to the public daily.
Fort McAllister
- Location: Richmond Hill, Georgia
- Constructed: 1861
One of three forts defending Savannah, Fort McAllister was the site of numerous Civil War battles. It was overtaken by Union infantry under General William B. Hazen, allowing General William T. Sherman to capture the city. The fort has been restored to its 1864 appearance and is now part of the Fort McAllister State Historic Park.
Fort Lytle
- Location: Bowling Green, Kentucky
- Constructed: 1861
Named Fort Vinegar when the Confederate Army built it in 1861, this fort is one of eight constructed around Bowling Green to protect supply lines from Nashville to Louisville. It was abandoned and subsequently taken over by Union troops in February 1861. The stone ruins and trenches are currently visible on the campus of Western Kentucky University.
Fort Pillow
- Location: Henning, Tennessee
- Constructed: 1861
Site of the Fort Pillow Massacre where Confederate troops, under the command of General Nathan Bedford Forrest, killed 300 African-American soldiers after they surrendered, rather than taking them as prisoners of war. It is currently a State Historic Park, parts of the inner fort have been reconstructed and a museum on site is open daily.