Boston Harbor Islands National Recreation Area | TOURING FORT WARREN (GEORGES ISLAND)

Inside Fort Warren on Georges Island in Boston Harbor

Inside Fort Warren on Georges Island in Boston Harbor

Georges Island Main Page


GUIDED TOURS

Park Rangers and volunteers at Georges Island in Boston Harbor Islands National Recreation Area conduct 45-minute tours of Fort Warren throughout the day. Announcements of upcoming tours are broadcast through a speaker system from the Georges Island Visitor Center. There is no need to register in advance, so just show up at the meeting place if interested. The tour does not cover the fort in detail, so you may want to walk around on your own afterwards.

Guide leads a tour of Fort Warren

Guide leads a tour of Fort Warren

SELF-GUIDED TOURS

Visitors to Georges Island are also invited to explore Fort Warren on their own. There are information panels posted throughout the fort, plus there is a Fort Warren Self-Guided Tour brochure available at the Visitor Center that contains additional information.

The entrance to the fort, known at the sally port, is located on the northwest side of the island. You can reach it in one of two ways, with the most obvious being from the ferry dock area. Look for a tunnel that leads into the dry moat.

Passage to moat at Fort Warren

Passage to moat at Fort Warren

Approaching the sally port by way of the moat

Approaching the sally port by way of the moat

The second way to reach the entrance is to walk around to the northeast side of fort, past the large picnic area, until coming to the demi lune, a crescent-shaped outer fortification that blocks a direct assault on the sally port. A paved pathway leads around the structure and to the entrance.

Demi lune guards the entrance to Fort Warren

Demi lune guards the entrance to Fort Warren

Either way you go, you will eventually come to a bridge that spans the moat and leads into Fort Warren.

Fort Warren sally port

Fort Warren sally port

Before entering, notice that the top of the fort’s outer wall, the scarp, is covered with dirt. The fort is pentagon shaped with a bastion at each corner. The wall where the sally port is located is called Front 3. It and Front 2, the next wall to the left when facing the entrance, as well as Bastions D and C, are situated along The Narrows, the only deep-water channel that led into Boston in the 1800s (it runs between Georges and Lovells islands). These walls and bastions would take direct fire from any enemy ships passing through the channel. The layer of earth is there to absorb the impact of artillery shells.

Earthen capped Bastion C at Fort Warren on Georges Island in Boston Harbor

Earthen capped Bastion C at Fort Warren on Georges Island in Boston Harbor

Once inside the fort, you will be on the parade ground. This is a large field where drills, inspections, and parades were held, as well as where games such as baseball and football were played. The parade ground is six acres in size.

Parade Ground at Fort Warren

Parade Ground at Fort Warren

Notice that three of the fort’s walls are lined with granite facades (Fronts 1, 2, and 3), while two are nothing more than earthen hills that slope to the top of the fort walls (Fronts 4 and 5). You can enter Front 1, but Fronts 2 and 3 are closed (they’re just more of the same, anyway). What you see inside are known as casemates: fortified rooms used to house artillery pieces.

Fort Warren (click to enlarge)

Fort Warren (click to enlarge)

Fronts 1 and 2 of Fort Warren

Fronts 1 and 2 of Fort Warren

Because artillery mounted in casemates had to be fired through an embrasure (hole in the wall), they had limited movement left to right and up and down as compared to guns mounted out in the open on the terreplein (top of the fort). However, the casemates offered superior protection for the guns and crew. Casemates also had arched roofs, a design that strengthened the ceiling so that it could support the upper floors of the fort.

Inside a casemate at Fort Warren on Georges Island

Inside a casemate at Fort Warren on Georges Island

Men could walk from casemate to casemate without exiting onto the parade ground through archways in the walls. Again, the arch design helped strengthen the roof of the lower floor.

Archway between casemates

Archway between casemates

Most of the embrasures were bricked up long ago. However, there are two cannon on display that demonstrate how the casemates would have been furnished. These guns are much smaller than the 10- and 15-inch Rodman guns that were originally installed at Fort Warren.

Cannon mounted in a casemate fire through an embrasure

Cannon mounted in a casemate fire through an embrasure

The grooves in the floor where cannon were once mounted held iron tracks. With the back wheels of the gun carriage placed on the tracks, the carriage could be swiveled left or right.

Bricked embrasure

Bricked embrasure

Six months into the Civil War, Fort Warren was turned into a prison for Confederate soldiers, Union deserters, and some political prisoners. Many of the casemates were converted into barracks, each housing a couple dozen men. Those in Front 1 were used to house enlisted men, both active-duty Union soldiers and Confederate prisoners. Those housing Union soldiers remained outfitted with artillery pieces. By the 1900s, the use of casemates to house artillery had become outdated due to technology, so some casemates were used to store gunpowder, shells, and supplies, while others were converted into offices and shops.

At the five corners of the fort are bastions: structures that protrude out from the fort walls. Armed men and cannon located in the bastion were able to shoot at enemy soldiers who reached the fort walls, whereas soldiers stationed along the wall would not be able to see and shoot such men.

Example of coverage possible by men stationed in a bastion

Example of coverage possible by men stationed in a bastion

In the Fort Warren satellite image above on this page, notice that Bastions C and D have open courtyards, while the other three do not. When built, all bastions had courtyards. Bastion B ended up becoming part of Battery Plunkett and Adams, which were built between 1892 and 1899. Bastions A and E were roofed over to provide platforms for more artillery pieces after the Civil War. The roofs also created additional interior rooms below. New rooms inside Bastion A were used for indoor training, a powder magazine, and wagon and gun carriage storage. Visitors are welcome to enter into Bastion A through what is called the Dark Arch. The inside is very dark and cavernous and would make for a great haunted house at Halloween, or as one guy said, the perfect place to play paintball.

Open courtyard of Bastion C at Fort Warren on Georges Island

Open courtyard of Bastion C at Fort Warren on Georges Island

Visitors enter Fort Warren's Bastion A through the Dark Arch

Visitors enter Fort Warren’s Bastion A through the Dark Arch

Interior casemates of Fort Warren

Interior casemates of Fort Warren

Bastion C, the only bastion that has never been altered from its original design, was where Fort Warren’s kitchen, mess hall, and commissary were located from the start of the Civil War until around 1900.

Ovens in the Fort Warren bakery

Ovens in the Fort Warren bakery

After visiting the ground floor of Fort Warren, take a tour of the terreplein: the level walking area at the top of the fort where guns were mounted. The terreplein is accessed by stairs along Front 2 near Bastion B and from a staircase in Bastion C. Three of the five terrepleins are accessible to the public.

Stairs leading up to the terreplein atop Front 2

Stairs leading up to the terreplein atop Front 2

Before the 1800s, forts in the United States did not regularly include casemates, so all guns were mounted on the top of fort walls and exposed to enemy fire. The only defense was a protective wall called the parapet. Even when casemates became a standard part of fort design, guns were still mounted on top because they had a much wider range both vertically and horizontally than those in the casemates.

While construction on Fort Warren was completed enough for it to be functional in 1851, no funding was provided for weapons. The fort was built to hold 334 guns, but it remained unarmed for another decade. It took the Civil War to break out in 1861 for guns to finally be installed, and even then it was never fully armed. It eventually held 200 guns, mainly 10-inch and 15-inch Rodman cannons, the largest artillery pieces of the time. Today, in addition to seeing the empty gun emplacements, one 15-inch Rodman gun mounted on a Barbette carriage is on display. The semicircular stone structures on the ground served the same purpose as the iron tracks in the casemates.

Rodman cannon at Fort Warren

Rodman cannon at Fort Warren

Empty gun emplacements

Empty gun emplacements

The terreplein of Front 1 was originally the same as Fronts 2 and 3, but it was replaced with concrete artillery batteries in the 1890s. The development of rifled artillery during the Civil War rendered masonry forts such as Warren obsolete. Masonry forts had no problem stopping a cannonball, for these didn’t travel with much velocity, nor were they very accurate, so the chance of blasting a hole in a fort wall by hitting the same spot over and over again was slim. However, rifled artillery had an inner barrel with a spiral grove cut into it. When fired, bullet-shaped shells were sent spinning like footballs, increasing not only their accuracy, but also their range and velocity. The effect these shells had on masonry forts was first demonstrated during the Union bombardment of Fort Pulaski on April 10-11, 1862 (Fort Pulaski National Monument). The walls of the “indestructible fort” were breached in less than thirty hours, forcing the Confederates to surrender…and effectively ending the days of the masonry fortresses.

After the war ended, the United States government realized the vulnerability of the existing forts, but with much of the country in ruin, financially it was not able to do much about the situation other than outfit the forts with modern guns. It wasn’t until the threat of war with Spain came about in the 1880s that President Grover Cleveland formed a military commission to come up with ideas for coastal defense upgrades. The new system, initiated by Secretary of War William Endicott and referred to as the Endicott System of Coastal Defenses, called for the installation of small concrete and rebar batteries that could withstand the impact of the rifled shells. While much smaller than traditional forts, they were armed with guns that could damage the armor-plated hulls of modern ships. Before the dawn of aviation, any invasion of the United States would most likely come from the sea.

Five batteries were installed on the grounds of Fort Warren between 1892 and 1902. Batteries Stevenson, Plunkett, and Adams replaced Front 1, while batteries Bartlett and Lowell were installed on the grounds outside the fort.

The first battery installed on Front 1 was Battery Adams in 1892. It held a single 10-inch M1888 gun mounted on an M1894 disappearing carriage. When looking at the batteries from the terreplein of Front 2, you will see three large, circular disappearing gun pits—Battery Adams is the one closest to you. It is also in the worst shape. Being an early battery, Adams was built with Rosendale cement, which quickly deteriorated in the salty and moist air. It was no longer used after 1914. Subsequent batteries were built using Portland cement.

Disappearing gun emplacement of Battery Adams

Disappearing gun emplacement of Battery Adams

Disappearing guns were just regular artillery pieces; it was the carriage that created the disappearing effect. A carriage was lowered below the battery wall to be loaded, then raised up over the wall to be fired. The recoil from the blast sent it back down to the loading position. The following video demonstrates a disappearing gun at Battery Chamberlain in San Francisco. These are 6-inch guns, but the concept of operation is the same.


The other two disappearing gun pits belong to Battery Stevenson, which was built between 1899 and 1902. It held two 12-inch M1895 guns—the most powerful at the time—mounted on M1897 disappearing carriages. Stevenson was in use until 1945. It is in much better shape that Adams, but access to all gun pits is now blocked by fencing.

Disappearing gun put of Battery Stevens, part of Fort Warren in Boston Harbor

Disappearing gun put of Battery Stevens, part of Fort Warren in Boston Harbor

The gun pits at Fort Warren have only recently been blocked off. When I visited in 2015, visitors could walk down into the pits. The two people in the photo below give a sense of scale to the empty gun emplacement.

One of two disappearing gun emplacements of Battery Stevenson

One of two disappearing gun emplacements of Battery Stevenson

The metal contraptions located in the walls at each gun pit are ammunition hoists. Shells were stored in the casemates below and moved to the gun level by electric hoists. Shells were then removed from the hoist and carted to the guns.

Ammunition hoist at Battery Stevenson

Ammunition hoist at Battery Stevenson

Close-up of the ammunition hoist door

Close-up of the ammunition hoist door

The red brick watchtower next to Bastion C was installed in 1900 and used to track targets for the guns mounted at Battery Stevenson. Once Fort Warren was converted into a mine control station during World War I and II, the tower was used to monitor ship traffic in the harbor.

Watchtower from 1900

Watchtower from 1900

Battery Plunkett, built at the same time as Stevenson, is situated near the concrete watchtower on the Front 2 terreplein. With the enormity of the adjacent disappearing gun pits, it’s hard to even notice it. Plunkett was armed with two 4-inch M1896 guns mounted on M1896 pedestal carriages. These were obsolete after World War I and removed in 1920.

Battery Plunkett at Fort Warren on Georges Island in Boston Harbor

Battery Plunkett at Fort Warren on Georges Island in Boston Harbor

Pedestal at Battery Plunkett where 4-inch M1896 guns were mounted

Pedestal at Battery Plunkett where 4-inch M1896 guns were mounted

When done exploring in interior of Fort Warren, you can explore more of the moat. However, it is impossible to walk all the way around—the moat ends at Bastion B.

Moat near Fort Warren's Bastion C

Moat near Fort Warren’s Bastion C

There are two other batteries on the south end of the island. Battery Bartlett, another early battery that was built between 1892 and 1899, is the largest of the two. It is not open to the public due to being in poor condition, plus it is located in the island’s maintenance area. Like Battery Adams, it was made of Rosendale cement, though it did hold up much longer.

Battery Bartlett at Fort Warren on Georges Island in Boston Harbor

Battery Bartlett at Fort Warren on Georges Island in Boston Harbor

Bartlett held four 10-inch M1888MI guns mounted on disappearing carriages. During World War I, two of the guns were removed and shipped to France, and the other two were removed for repair. After the war, all four were replaced with new guns, but by World War II the battery was obsolete. The guns and carriages were scraped in 1942. Part of the battery was demolished in the 1970s, which is why there are only three gun emplacements today instead of four.

Battery Lowell is the smaller battery located by the picnic area. It was constructed between 1899 and 1900 and outfitted with three 3-inch M1898MI guns mounted on M1898 masking parapet carriages. These guns were obsolete by 1920, at which time they were scraped and the battery decommissioned. It is accessible to the public.

Battery Lowell at Fort Warren on Georges Island in Boston Harbor

Battery Lowell at Fort Warren on Georges Island in Boston Harbor

Gun emplacement on Battery Lowell on Georges Island

Gun emplacement on Battery Lowell on Georges Island

Front side of Battery Lowell

Front side of Battery Lowell

SCHEDULING YOUR TIME

I took the Ranger tour of Fort Warren, which lasted about 45 minutes, then explored the fort on my own for another hour. I didn’t do anything out of the ordinary, so an hour should work for most self-guided tours.

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Last updated on September 17, 2021
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