At sunrise on September 6, 1781, the British destroyed a number of ships and an "immense" stockpile of goods and naval stores and burned one hundred and forty-three buildings, nearly all in the town of New London.
The British force of 800 that landed on the east side of the Thames River was slowed by the tangled woods and swamps but came within striking distance of Fort Griswold by 10:00 a.m.. Fort Griswold had been garrisoned with about 150 militia and local men, expecting reinforcements momentarily, elected to defend the post against the superior force. The British force immediately spread their ranks and advanced on Fort Griswold, reached a cannon and turned it against the garrison, reached the gate and opened it and the enemy force marched in. The Fort Griswold men were ordered to stop fighting by their leader Colonel Ledyard. The Americans obeyed but the British continued to shoot the defenseless Americans. In this confusion Colonel Ledyard was killed with his own sword after which a horrible massacre ensued. Before the "massacre" it is claimed that less than ten Americans had been killed, but when it was over, more than eighty of the garrison lay dead and mutilated and more than half of the remainder were severely wounded. The entire battle had lasted only 40 minutes.
Thirty-five wounded men were taken to the nearby Ebenezer Avery's house, hastily placed on the bare floor where they lay all night without care. Ebenezer Avery was among them.
All survivors who could walk (28),were packed on board British vessels for New York. Here they were held prisoners until Nathaniel Shaw was able to arrange for their release.
Fort Griswold was the scene of military defense preparations in at least four other wars. The water battery was rebuilt and rearmed several times but the fort itself retains its original form.
The General Assembly later repaid the money losses from the "late hostile invasion of the enemy." In 1792,"Five hundred thousand acres of the land belonging to the State of Connecticut, lying west of the State of Pennsylvania and bounded northerly on the shore of Lake Erie, known as the "Firelands", was awarded to those who suffered from enemy action, to be divided to and among the said sufferers and their legal representative where they are dcd in proportion to the several sums annexed to their names."
The list of beneficiaries in Groton is as follows:
| E | s. | d. | |
| Prudence Avery | 270 | 14 | 8 |
| Thankful Avery | 263 | 18 | 8 |
| Rufus Avery | 132 | 18 | 8 |
| Lydia Avery | 157 | 12 | 1 |
| Amos Avery | 12 | 2 | 2 |
Few Groton victims benefited from this land; it was too far away to be of much use. At present we have Groton, Norwich and New London townships in Erie and Huron counties, which were probably named for the towns in Connecticut and the town of Avery just northwest of Milan. Fort Avery, northeast of Milan, was the county seat in 1811 and the names of Amos and Thankful Avery are mentioned in the history of the area. Further research is planned.