The Battle of Groton Heights, September 6, 1781: The Fort Griswold Massacre

Part One

Benedict Arnold
Benedict Arnold

After turning coat, Benedict Arnold received a commission as a brigadier general in the British army as part of the deal that he made in order to betray his country.

In August 1781, George Washington decided to shift forces in order to attack the army of Lt. Gen. Lord Charles Cornwallis in Virginia. Washington began pulling troops from the New York area. Lt. Gen. Sir Henry Clinton, the British commander-in-chief in America, realized on September 2 that Washington’s tactics had deceived him, leaving him unable to mobilize quickly enough to help Cornwallis. Further, there was still a significant force of Continentals facing him in front of New York, and Clinton did not feel that he could detach troops to reinforce Cornwallis as a result.

Sir Henry ClintonInstead, Clinton decided to launch a raid into Connecticut in the hope of forcing Washington to respond. Clinton intended that this be a raid, but he also recognized that New London could be used as a permanent base of operations into the interior of New England. Clinton appointed Arnold to command the raid because he was from Connecticut and knew the terrain.

Arnold commanded about 1,700 British solders, divided into two battalions. Lt. Col. Edmund Eyre commanded a battalion consisting of the 40th and 54th Regiments of Foot and Cortland Skinner’s New Jersey Volunteers, a Loyalist unit. Arnold himself commanded the other battalion, made up of the 38th Regiment of Foot and various Loyalist units, including the Loyal American Regiment and Arnold’s American Legion. Arnold also had about 100 Hessian Jägers, and three six-pound guns. This was a formidable force anchored by the three Regular regiments.

Arnold and his command sailed from New York City on September 4. The British fleet anchored about 30 miles west of New London to make its final preparations, and then sailed for New London late on September 5, hoping to make a nighttime landing. Fortunately for the defenders of New London, the winds did not favor Arnold’s plan, and the British force did not arrive until daylight on September 6.

Rufus Avery, a Continental officer stationed at Fort Griswold, on the opposite side of the Thames River, and positioned on commanding high ground, witnessed the arrival of the British:

          “… about three o’clock in the morning, as soon as I had daylight so as to see the fleet,              it appeared a short distance below the lighthouse. The fleet consisted of thirty-two
vessels…. I immediately sent word to Captain William Latham, who commanded
[Fort Griswold], and who was not far distant. He very soon came to the fort, and saw            the enemy’s fleet, and immediately sent a notice to Col. William Ledyard, who was
commander of the harbor, Fort Griswold, and Fort Trumbull.”

43-year-old Lt. Col. William Ledyard commanded Forts Griswold and Trumbull. Ledyard, a Connecticut militia officer, quickly sent a messenger to notify Gov. Jonathan Trumbull and to muster troops. He then went to Fort Griswold to assume command of its defenses. The fort’s guns fired twice to signal the enemy approach, and a British ship answered with a third shot, changing the meaning of the signal to suggest the arrival of a victorious friend, thereby confusing the local militia commanders and delaying the mustering and deployment of their troops.

Map of Fort Griswold drawn by a British officer.
Map of Fort Griswold drawn by a British officer

Fort Griswold began being constructed in late 1775 in response to the outbreak of hostilities. It was completed in 1778, and was known as “Groton Fort.” It sits atop a high hill and could bombard any ship attempting to enter the Thames River or the town of New London. Approximately 165 Connecticut militiamen manned its defenses, organized into two companies, and a detachment of the 8th Regiment of Connecticut Militia. Ledyard and his soldiers face a stern task—they were badly outnumbered by veteran British troops including Regulars of some of the best regiments in Clinton’s army.

A British officer described Fort Griswold’s defenses:

         “The fort was an oblong square, with bastions at opposite angles, its longest side
fronting the river in a north-west and southeast direction.  Its walls were of stone,
and were ten or twelve feet high on the lower side, and surrounded by a ditch.  On the
wall were pickets, projecting over twelve feet; above this was a parapet with
embrasures, and within a platform for cannon, and a step to mount upon, to shoot
over the parapet with small arms.  In the south-west bastion was a flag-staff, and in
the side near the opposite angle, was the gate, in front of which was a triangular
breast-work to protect the gate; and to the right of this was a redoubt, with a three-
pounder in it, which was about 120 yards from the gate.  Between the fort and the
river was another battery, with a covered way, but which could not be used in this
attack, as the enemy appeared in a different quarter today.”

Six-pound cannons bristled from the western side of the fort, overlooking the Thames. The northern side by the main entrance was level and played a major role in the coming battle.

A view of New London and the Thames River from Fort Griswold
A view of New London and the Thames River from Fort Griswold (author collection)

At sunrise on September 6, British troops landed on both sides of the mouth of the Thames River. Arnold’s battalion of 800 men occupied New London with no resistance. The 23 soldiers manning Fort Trumbull on the New London side of the river fired a single volley, spiked their guns, and then fled across the river to Fort Griswold. Shapley lost 7 men wounded while Arnold’s troops sustained four or five casualties. After chasing off the defenders of Fort Trumbull, Arnold’s troops entered the town and began destroying supplies and naval stores. Parts of the town were spared, but when a storehouse that contained a large supply of gunpowder was set ablaze, the resulting explosion triggered a huge fire that consumed 143 buildings in New London.

5 thoughts on “The Battle of Groton Heights, September 6, 1781: The Fort Griswold Massacre

  1. Pingback: Part Two: The Battle of Groton Heights, September 6, 1781: The Fort Griswold Massacre | Emerging Revolutionary War Era

  2. If Sir Henry Clinton really intended to pressure Washington into returning, why did the raiding force consist of only 1700 men, why wasn’t Arnold reinforced after his success, and why didn’t Clinton follow through with his intention of establishing a base in Connecticut?


  3. Eric J. Wittenberg

    I don’t have a good answer for you, Mr. Herling. Apparently, there was some inkling of the state of affairs in Virginia, but I cannot say for certain.


  4. Most likely, the neurotic Clinton was terribly afraid of leaving significant numbers of British or Hessian troops outside of New York. He had thoroughly convinced himself that the city, his headquarters, was always threatened by the rebels, regardless of the weakness of the rebel forces anywhere near the city.


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