Battle of Groton Heights The Battle of Groton Heights ( also known as the Battle of Fort Griswold , and occasionally called the Fort Griswold massacre ) was a battle of the American Revolutionary War fought on September 6 , 1781 , between a small Connecticut militia force led by Lieutenant Colonel William Ledyard and the more numerous British forces led by Brigadier General Benedict Arnold and Lieutenant Colonel Edmund Eyre . In an unsuccessful attempt to divert General George Washington from marching against Lord Cornwallis ' s army in Virginia , Lieutenant General Sir Henry Clinton ordered General Arnold to raid the Connecticut port of New London . Although the raid was a success , the Connecticut militia stubbornly resisted British attempts to capture Fort Griswold , across the Thames River in Groton . Several leaders of the attacking British force were killed or seriously wounded , and much of the defending garrison was either killed , mortally wounded , or captured when the fort was stormed . High British casualties lead to criticism of General Arnold by some of his superiors . The battle was the last major military encounter of the war in the northern United States , preceding the decisive American victory at Yorktown , Virginia , by about six weeks . Background . With its history dating back to 1655 , Groton , Connecticut was originally a part of New London , its larger counterpart on the other side of the Thames River on the northern shore of Long Island Sound . Groton was an important maritime port , and became one of the largest along the New England coastline . Groton officially separated from New London and incorporated as a separate town in 1705 . During the American Revolutionary War , the port was a major center of rebel naval operations , including highly successful privateer ing operations against British shipping . The port , however , was comparatively poorly protected : Fort Trumbull , on the New London side , was little more than a redoubt open on the inland side , while Fort Griswold in Groton was a more substantial , roughly square , bastioned stone fort surrounded by a ditch and some outer earthen defenses . They were typically garrisoned by small companies of militia , including a few artillerymen , and overall command of the area ' s defenses was directed by Lieutenant Colonel William Ledyard . The forts suffered from continuous shortages of provisions and equipment . In the case of Fort Trumbull , the fort itself was unfinished . Although Fort Griswold ' s infrastructure was complete , it lacked sufficient gunpowder , cannonballs , food , and troops to conduct an effective stand against the British . In August 1781 , Continental Army Major General George Washington realized there was an opportunity to strike at the British army of Lieutenant General Charles , Earl Cornwallis , in Virginia . Using a variety of strategems to deceive the British Commander - in - Chief and head of the British forces in New York City , Lieutenant General Sir Henry Clinton , Washington began moving his forces south from the New York area . General Clinton realized on September 2 that he had been deceived . Unable to mobilize quickly enough to assist Cornwallis , and unwilling to detach a large percentage of his forces in the face of the Continental forces Washington had left around New York , Clinton decided to launch a raid into Connecticut in an effort to draw Washington ' s attention . Though Clinton only planned it as a raid , he also believed that if a permanent British occupation of New London could be established , it could be used as a base for further operations into the interior of New England . He gave command of the forces for the raid to Norwich , Connecticut native Brigadier General Benedict Arnold , who had changed sides the previous September . Prelude . The forces assembled by the British were divided into two battalions , numbering about 1 , 700 men . The first , under Lieutenant Colonel Edmund Eyre , was composed of the 40th and 54th Regiments of Foot and a Loyalist provincial regiment , Cortlandt Skinner ' s New Jersey Volunteers . The second battalion , under Arnold ' s command , consisted of the 38th Foot and a variety of Loyalist units , including the Loyal American Regiment and Arnold ' s provincial regiment , known as the American Legion . The expedition also included about 100 Hessian jäger s , a small number of artillerymen , three six - pound guns , and a howitzer , all of which were divided between the battalions . These troops were embarked on transports , and sailed on September 4 in the company of a fleet of smaller armed ships led by Commodore John Bazely in the fifth - rate . The fleet anchored about west of New London to make final preparations , and then sailed for New London late on September 5 , intending to make a nighttime landing . However , contrary winds prevented the transports from reaching the port until it was already daylight on September 6 . In the early hours of that morning Rufus Avery , a colonial officer stationed at Fort Griswold , witnessed the fleet ' s arrival : " . . . 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 . " Upon receiving the alert , Ledyard sent a messenger to notify Governor Jonathan Trumbull and local militia leaders of the British arrival , and went to Fort Griswold to arrange its defenses . Fort Griswold ' s guns were fired twice , a signal of enemy approach . However , one of the British ships fired a third round , changing the meaning of the signal to indicate the arrival of a victorious friend . This signal confusion led to delays in the mustering of militia companies . At sunrise on September 6 , the British landed on both sides of the mouth of the Thames River . The people of the town could do nothing but evacuate , and several ships in the harbor escaped upstream . The 800 - man detachment that Arnold led in New London met with no resistance . The defenders of Fort Trumbull , 23 men led by Captain Shapley , following orders left by Colonel Ledyard , fired a single volley , spiked the guns , and boarded boats to cross the river to Fort Griswold . Seven of Shapley ' s men were wounded , and one of the boats was captured ; the detachment Arnold sent to take Fort Trumbull lost , according to Arnold ' s account , four or five killed or wounded . Arnold ' s troops continued into the town , where they set about destroying stockpiles of goods and naval stores . Under the orders given , much of the town was supposed to be spared ; but unknown to Arnold , at least one of the storehouses burned contained a large quantity of gunpowder . When it ignited , the resulting explosion set fire to the surrounding buildings . The fire was soon uncontrollable and 143 buildings were consumed by flames . Several ships in the harbor were able to escape upriver when the wind changed . Meanwhile , Lieutenant Colonel Eyre ' s force of 800 men that landed on the east side of the Thames River was slowed by tangled woodlands and swamplands . The New Jersey Loyalists landed after the initial wave of regulars , also delayed by the difficulty in moving the artillery through rough conditions , and did not participate in the assault . George Middleton , a boy of 12 ( who in some accounts is incorrectly confused with George Middleton , the commanding officer of an African American militia unit called the Bucks of America ) witnessed the quick rallying of Ledyard ' s militia and the landing of the British regiments , which he reported occurred between 10 : 30 and 11 : 00 am : " The other division of troops landed on the east side of the river . . . under the command of Col . Eyre and Major Montgomery . This division . . . got to the terminus of the woods . . . a little south of east on a direct line from the fort . Here the division halted , and Major Montgomery sent Captain Beckwith with a flag to the fort to demand its surrender . Colonel Ledyard . . . sent a flag and met Beckwith . . . The bearer of the American flag answered , ' Colonel Ledyard will maintain the fort to the last extremity . ' " Eyre sent a second parley flag , threatening to give no quarter if the militia did not surrender . Ledyard ' s response was as before , even though some of his subordinates argued that they should leave the fort and fight outside it . General Arnold ordered Eyre to assault the fort , believing the fort would fall easily . However , upon reaching a prominence from which he could see its defenses , Arnold realized that the fort was more complete than anticipated and that taking it would not be easy . Since one of the reasons for taking the fort was to prevent the escape of boats upriver , and many had already passed beyond the fort , Arnold attempted to recall Eyre , but the battle was joined a few minutes before the messenger arrived . Battle . On the return of the second parley flag , Eyre launched a full scale assault upon the fort and its roughly 150 defenders . Stephen Hempstead , a sergeant in Ledyard ' s militia recounted , " When the answer to their demand had been returned . . . the enemy were soon in motion , and marched with great rapidity , in a solid column . . . they rushed furiously and simultaneously to the assault of the southwest bastion and the opposite sides . " As the British neared the ditch , they were met by a bombardment of grapeshot that killed and wounded many . This briefly scattered the British , who reformed into two units . Eyre led one force against the southwest bastion , where American fire repulsed the assault , seriously wounding Eyre and several of his officers . ( New London historian Frances Manwaring Caulkins ' assertion that Eyre was mortally wounded is apparently incorrect ; Arnold reported that Eyre survived . ) Major William Montgomery led the second party to an abandoned redoubt just east of the fort . From there they moved across the ditch and assaulted the ramparts . Against fierce resistance this unit gained the bastion , but Montgomery was instantly killed by a bayonet thrust . Montgomery ' s men were finally able to open a gate from inside , and the British force poured into the fort . Seeing that the fort was penetrated , Colonel Ledyard ordered a cease fire and prepared to surrender the place . What happened next was a subject of some controversy . The most detailed extant accounts of the event are from American sources , but are fairly consistent in what they describe . According to these accounts , the British continued to fire on the Americans despite Ledyard ' s signs of surrender , and much of the garrison was consequently either killed or seriously wounded . Rufus Avery wrote in his account , " I believe there was not less than five or six hundred men of the enemy on the parade in the fort . They killed and wounded nearly every man in the fort as quick as they could . . . " Jonathan Rathbun described the cold - blooded killing of Colonel Ledyard with his own sword by an officer : " . . . the wretch who murdered him [ Ledyard ] , exclaimed , as he came near , ' Who commands this fort ? ' Ledyard handsomely replied , ' I did , but you do now ' , at the same moment handing him his sword , which the unfeeling villain buried in his breast ! Oh , the hellish spite and madness of a man that will murder a reasonable and noble - hearted officer , in the act of submitting and surrendering ! " Some accounts claim that Captain George Beckwith killed Colonel Ledyard , while others claim it was Captain Stephen Bromfield , who assumed command after Major Montgomery was killed . Stephen Hempstead recalled the bloody scene in the aftermath : " Never was a scene of more brutal wanton carnage witnessed than now took place . The enemy were still firing upon us . . . [ until ] they discovered they were in danger of being blown up . . . " Rufus Avery believed the attack was called off due to the chance that further musket fire might set off the fort ' s powder magazine . American accounts and historical descriptions ascribe several possible reasons for the British behavior . During the battle , the fort ' s flag was supposedly shot down at one point . Although it was quickly reraised , some of the British attackers interpreted the event as striking the colors , making a sign of surrender ; the British suffered significant casualties when they then approached the fort on that occasion . Combined with anger over the death and wounding of their commanding officers , this led them to disregard Ledyard ' s legitimate surrender . Some accounts also claim that Americans in one part of the fort were unaware that Ledyard had surrendered , and continued to fight , leading the British to also continue fighting , even against those who had surrendered . Early British historians generally did not report much beyond Arnold ' s report of the expedition , which did not mention killings after the surrender . William Gordon , however , reported in his 1788 history of the war that " [ t ] he Americans had not more than a half dozen killed " before the fort was stormed , and that " a severe execution took place after resistance ceased . " An Italian historian wrote in 1809 that " [ t ] he assailants massacred as well those who surrendered as those who resisted . " Aftermath . The massacre at Fort Griswold marked one of the largest tragedies in the history of Groton and Connecticut , and was one of the last British victories in North America before the end of the war . Damage to New London was substantial : one estimate placed the value destroyed at nearly $ 500 , 000 . The battle left nearly 100 families homeless , destroyed nine public buildings , and much of the town ' s waterfront . The state in 1792 identified losses that totaled more than £61 , 000 , or $ 200 , 000 Continental dollars . Some who lost homes or property were awarded land in the Western Reserve . The slaughter at Fort Griswold left dozens of Americans dead . The " Groton Gazette " reported that casualties numbered about 150 . Some survivors , such as George Middleton , escaped , but others , including Stephen Hempstead , were taken prisoner . He stated , " After the massacre , they plundered us of everything we had , and left us literally naked . . . " Hempstead , who was among the wounded , reported how he was placed on a wagon with others to be taken down to the fleet . The wagon was allowed to run down the hill , where it stopped when it struck a tree , throwing some of the men off the wagon and aggravating their injuries . General Arnold reported that 85 men " … were found dead in Fort Griswold , and sixty wounded , most of them mortally . " Benedict Arnold later issued a report stating that 48 British soldiers were killed and 145 wounded . General Clinton praised Arnold for his " spirited conduct " , but also complained about the high casualty rate ; about 25 percent of the troops sent against Fort Griswold were killed or wounded . One British observer wrote that it had been like " a Bunker Hill expedition , " and many British soldiers blamed Arnold for the events at Fort Griswold , even though he had not been in a position to prevent the reported slaughter . Arnold next proposed a raiding expedition against Philadelphia , but the surrender of General Charles Cornwallis at Yorktown in late October ended that idea . Legacy . Although the British left a burning powder trail to destroy Fort Griswold ' s magazine , a daring militiaman entered the fort and extinguished the fire . Both Forts Trumbull and Griswold were extensively modified in the 19th century , and are now preserved in state parks . The Fort Griswold park also includes the Groton Monument , erected in the 1820s to commemorate the battle . Both forts are listed on the National Register of Historic Places .