The raid, led by Commodore Sir George Collier, was executed in an attempt to head off a planned second assault on Fort Cumberland, which had been besieged in November 1776.

The small community of Machias, located in the eastern district of Massachusetts that is now the state of Maine, was a persistent thorn in the side of British naval authorities since the start of the American Revolutionary War.

[4] In early August the Massachusetts Provisional Congress voted to disband forces recruited for Allan's expedition because of the imminent threat posed by the army of General John Burgoyne in upstate New York.

[5] Papers documenting Allan's fairly elaborate plans, including a projected attack on Fort Cumberland, were taken during the conflict on the St. John River and fell into the hands of Captain Sir George Collier, second-in-command to Admiral Mariot Arbuthnot in the naval station at Halifax.

[6] The defense of Machias consisted of local militia under the command of Colonel Jonathan Eddy, the leader of the 1776 attack on Fort Cumberland.

The militia laid a log boom across the Machias River, and constructed several earthen redoubts further upriver, armed with cannons taken from local privateers.

[4] The defense was coincidentally reinforced by forty to fifty Maliseet, Passamaquoddy, and Penobscots that Colonel Allan had called to Machias to explain what had gone wrong with his expedition.

At this point, "To the great Surprise and Astonishment of every one[,] in Less than half an Hour after Coming to an Anchor, the Brig & Sloop Both Gote under way without firing a Gun" and "made down the River against the Tide of flood.

The militia hauled a swivel gun to a nearby shore, and peppered her with shot the next morning before she was refloated by the tide and made her way into Machias Bay.

[6] After departing from Machias, Collier cruised the Maine coast, capturing smaller American ships, and raided communities on the Sheepscot River.