As soon as it was determined to make an attack on Louisbourg, Commodore Warren was directed to proceed to Canso from the Leeward Islands, to take command of the naval operations. On the 4th of April the levies from New England were encamped on Canso Hill, to await the arrival of the rest of the troops; while some ships of war, with several large privateers, continued off the harbour of Louisbourg, in order to cut off all supplies.
On the 23rd of April, Commodore Warren, with the Superb 60 guns, Eltham 40, Launceston 40, and Mermaid 40, arrived at Canso, and after conferring with General Pepperell, the squadron proceeded off Louisbourg ; and on the 29th the troops, amounting to 4000 provincials, and 800 seamen and marines, were conveyed to Garbarus Bay, about four miles distant.
On the 30th, 2000 men landed, and beat back the enemy who had opposed their debarkation ; and on the following day the commodore landed the remainder of the troops and the Marines from the ships, and they were formed into two separate encampments ; one on the south side of the harbour to attack the city, and that on the northern against the grand battery.
During the night of the 1st of May our picquets set fire to some storehouses ; and the French, conceiving that the whole British force was advancing, retreated precipitately into the city.
The enemy's works were quickly occupied by the British, and continued to be held in defiance of all their efforts to regain them. The force on the north side of the harbour had pushed
their advances to within two hundred yards of the city by the 12th of May, and the cannonade was spiritedly maintained from some heavy ordnance on an eminence called the Green Hill,
and a fascine battery mounting twenty-eight guns. The siege was carried on under great difficulties; but every thing was well conducted, and some important captures by the squadron of ships bringing supplies from France, accelerated the fall of the colony of Cape Breton.
A force of 200 Marines and 300 Americans embarked in the boats to attack the island battery at midnight, on the 23rd of May ; but owing to a dense fog, they failed in effecting a landing. On the 27th, another detachment, consisting of 150 Marines and 200 provincials, proceeded on this enterprise ; but the enemy were prepared for their approach, and opened a heavy and destructive fire on the boats : nevertheless, the troops pushed gallantly ashore, and persevered in their efforts to scale the walls until sunrise; by which time they were so reduced in number, as to be compelled to surrender themselves to the enemy.
On the 12th of June, by great exertion, some cannon were planted on a cliff which commanded the platform of the island battery ; and after forty-nine days of unceasing exertion, Louisbourg capitulated, and with it the whole dependency of Cape Breton, which was accomplished with the loss of about 100 men, while that of the enemy exceeded 300.
The reduction of this settlement was of great importance to Great Britain, as well as to our North American possessions : it freed the northern colonies from a powerful neighbour, overawed the Indians of that country, and secured the possession of the province of Nova Scotia. At the same time, it distressed the French in heir fishing and navigation, and removed all apprehension of encroachment or rivalship with our establishments on the coast of Newfoundland.