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The Battle of Groton Heights

Updated: Sep 4

The Battle of Groton Heights / The story of Fort Griswold

Groton Connecticut / Sept. 6th 1781

Written and provided by: Jack Currier, Idaho SAR


Fort Griswold is located in Groton, Connecticut, about three miles from the mouth of the Thames River that flows into Long Island Sound. It is on the east or Groton side of the river. About a mile south and on the west side of the river in New London is Fort Trumbull.









New London was established in 1646 and was the largest harbor on the Long Island Sound. This made it a very important waterway for the New England Colonies.


Fort Griswold and Fort Trumbull were built to protect the river. Until the Revolution, the river was used mostly for importing and exporting goods of various types. Fort Griswold was a Star Bastion fort and in a more formidable defensive position than Fort Trumbull. It was built on top of a high hill with a lot of swamp land to the south, making it difficult for an infantry attack. Fort Trumbull was not as yet completed, lacking the entire western and southwestern walls.


During pre- Revolution and early revolutionary days, most British troops were deployed in the Boston area. The start of the war was due to rising tension between the colonists, Tories and the British troops. The actions in Boston, the Tea Party, Boston Massacre and the Stamp Act are a story of their own. Things finally came to a head at Lexington and Concord Massachusetts on April 19th 1775. And so the war began. Here we will concentrate mainly on Fort Griswold and some on Fort Trumbull in Connecticut.


Once the bulk of the British troops moved from the Boston area to New York (York City), the troops numbered around thirty five thousand.

From shipping docks on the Thames River, mainly from the New London side, the colonists constantly launched Privateers to intercept and loot British supply ships. These were mainly legal (as far as colonists were concerned) pirate ships and a huge nuisance to the British. The colonists successfully captured the HMS Hannah (a British supply ship) and brought it to New London. The British wanted to stop this activity in New London as it severely limited their fighting capabilities.

The British would retaliate by attacking smaller more vulnerable Connecticut coastal towns. Stonington was one, but they fought back fiercely and the British left. Stonington was the only town in the country to be attacked in both the Revolutionary and the War of 1812 by the British.

But most towns gave up after a couple cannon fires from British ships and would supply the British with food and other needed supplies.



Benedict Arnold - Click photo to learn more

Benedict Arnold was a traitor, born in nearby Norwich, Connecticut, who defected to the British in West Point, New York in 1780. The fact he was a turncoat made him hated by the colonists and Washington wanted him hanged. He wasn’t trusted by the British either because he had already proven to be a traitor. During his time with the Continental Army, he was wounded in his left leg twice. Colonist would say to cut off his left leg and bury it with honors, and hang the rest of him.

Before he turned, he was the head of the New Haven Militia that marched on Boston. He was instrumental in the attack on Fort Ticonderoga, New York, and seized it without a shot being fired. He captured the cannons and brought them to Boston which helped push the British out of the Boston area. If he had not turned, he probably would have had a much different place in American history, that of a hero.


The defenders of Fort Griswold were not Continental Army but rather Connecticut Militia. They numbered about one hundred sixty eight with others joining the fight as it progressed. The same at Fort Trumbull, but their numbers were only about twenty three.

The British strategy for attacking Fort Griswold and the shipping docks of New London was to attack the Privateers and reclaim the HMS Hannah which they believed was being held in New London. They needed to turn Washington back towards the north, because Cornwallis was not ready for the battle in the Yorktown area after the French showed up and developed a blockade. Arnold thought if he could start a large enough battle in the north, Washington would turn around. That didn’t happen. The British also wanted to open a permanent base in Connecticut which would enable them to launch attacks throughout the northern colonies.


Under orders of British General Clinton, General Arnold departed New York City on September 5th 1781 under cover of darkness He had approximately twenty six to thirty two ships. (exact number is not known) and sixteen hundred foot soldiers. He halted his ships about twenty miles west of the mouth of the Thames River, just off Old Saybrook Connecticut. Winds had shifted and Arnold could not move his ships as quickly as he wanted. His plan was to be at the mouth of the Thames River before daybreak. Another impediment occurred because when he did reach the mouth of the river the tide was moving out and he was unable to proceed up the river. It was just daybreak and they were spotted by a twelve year old boy. He alerted some men in the area of what he saw. The fort was not manned heavily at this time and the commander Colonel Ledyard had to be summoned to post.

The signal of an attack was two cannon fires. The signal when the Privateers returned with loot was three cannon fires. Benedict Arnold knew this. So when the colonist fired two cannon shots Arnold followed it with a third. Now the militia in the immediate area saw and heard this, but the farmers and store owners, five to ten miles away did not. They couldn’t tell the difference. They just thought it was a Privateer ship returning to port. So response was very slow. Eventually the word got out that the enemy was approaching and they started to get into defensive positions in both forts.


Arnold dropped of eight hundred foot soldiers on the Groton side, present day Avery Point, part of the today’s University of Connecticut, and eight hundred foot soldiers on the New London side, present day Ocean Beach.

Moving north on the Groton side was slow going for the foot soldiers. It was mostly marsh and swamp.


The New London side moved much faster and as soon as the occupants of Fort Trumbull knew this, they fired one shot from each of their six cannons and then “spiked” the cannons by hammering nails into the fuse ports and broke them off, rendering them disabled. They didn’t want the British turning their own cannons on them. They jumped into boats and started rowing across the river towards Fort Griswold. Remember, there were no west or southwest walls yet. They were defenseless. A couple of the boats capsized and they were captured. It is not known how many actually made it across but it is estimated to be about ten of the twenty three made it.


The British foot soldiers on the Groton side did not know exactly where the fort was and found a young boy playing and made him lead the way to the fort.


The British finally arrived at Fort Griswold about 11:00 am and sent a messenger under white flag to demand unconditional surrender. At that time there was one hundred sixty six men at the fort. Colonel Ledyard held counsel with his officers and knew he could not defend the fort with one hundred sixty six men. There was another Militia Colonel there (name unknown) who said if he could hold the fort he would have another two hundred-three hundred men there within half an hour. So with the expectation of three hundred sixty five men that it would be possible to successfully defend the fort. Now Fort Griswold had twelve-sixteen cannons, The British couldn’t drag their cannons through the swampy terrain and Colonel Ledyard knew this. He refused to surrender. Arnold responded that if they had to take the fort by storm than no quarter would given. Meaning they all would be killed. Colonel Ledyard responded “I will not give up the fort, let the consequences be what they may.”


The British surrounded the fort and attacked. They were driven back. They assaulted again and were again were driven back. During these two assaults, two of the higher ranking British officers were killed, British Major Montgomery and British Colonel Eyers. They were in command at that time of the Groton side and the attack on Fort Griswold. The British sustained severe casualties. Arnold was at this time on the New London side. His orders were to burn the shipping docks but not to destroy civilian homes or structures.

The British actually considered giving up the assault on Fort Griswold and rejoining forces of Arnold on the New London side. During this little dilemma, they were still firing on the fort from down below. One of the rounds hit the flagpole flying over Fort Griswold and knocked it down. Lowering the flag was a sign of surrender. Now the British were happy and formed columns and marched towards the fort to take it over. The colonists opened fire on the British. This infuriated the British and they hit with full force. Breaching the south and east walls, they were now in the fort. Colonel Ledyard realizing they have been over run ordered everyone to lay down their arms.

British Major Bromfield approaches and asks “Who commands this fort?” Colonel Ledyard responds “I did but you do now sir,” and hands Major Bromfield his sword, handle first. Major Bromfield then shoves Colonel Ledyard’s own sword and runs him through, killing him. There was an estimate of six dead and fifteen wounded at the time of the surrender.






A massacre ensued. The British were killing everyone. Shooting, bayonets absolutely no quarter. Some retreated into the barracks, some retreated into the powder magazine, and they were pursued and butchered.


That essentially ended the battle. Of the colonists, there were eighty eight dead. One hundred fifty one of one hundred sixty six dead or wounded. The British left the wounded colonists naked in the sun and placed their own wounded in shaded areas. Per population, it was the deadliest battle of the war. Twenty-eight wounded that could be moved were taken prisoner and put on one of the British ships and taken to New York. The thirty five wounded who could not walk were ordered into an ammo wagon and taken to the top of the hill. They were pushed down the hill and went bouncing down the rough terrain until it collided with an apple tree at the bottom of what is now Latham and Thames Streets. The British still wanted to take them prisoner. Colonel Ledyard’s brother offered to have them take him prisoner instead, as he knew these men would never survive. Arnold agreed. These wounded were taking to the Avery house, mainly for shelter. They had no supplies to help them at all. Ebenezer Avery was of a prominent family in the area, and his house was close to the fort. He was actually wounded and taken prisoner and one of the men in the ammo cart. The Avery’s still have a large presence in the area to this day.


British casualties were seventy one dead, one hundred thirty one wounded and seventy deserted.


Arnold was mainly on the New London side to burn the shipping docks. Claims that the wind shifted westward resulted in the destruction of one hundred forty three buildings including a church, and sixty homes. On the Groton side, twenty one buildings and twelve homes were destroyed. The New London Waterfront was completely destroyed. Six ships out of twenty were destroyed. Fourteen actually escaped upriver.


The Battle of Groton Heights at Fort Griswold was the second to the last battle of the Revolution, followed only by the Battle of Yorktown Virginia and the British surrender.

The Battle was the last in the northern colonies and the bloodiest battle in Connecticut history.


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