After the fort was taken over by the British, with the new name of Fort Cumberland, new barracks were constructed both inside and outside the walls. Although these new facilities could house up to 800 soldiers, they were rarely occupied by more than a detachment of about 200.

The soldiers took advantage of every opportunity to amuse themselves. In 1756, for example, British soldiers brought in the New Year by roasting a variety of meats outdoors. St. Patrick's, St. George's and St. David's were always accompanied with festivities, as were the birthdays of the Royal Family.

In the early 1760s, a British engineer recommended, without success, that the fortifications be strengthened since they would never withstand a sustained artillery attack. French engineers had made similar observations in the past.

In 1763, with peace restored, Fort Cumberland was no longer of strategic importance although it continued to be manned by British troops until 1768. It was occupied temporarily in 1776 during the American War of Independence by about 275 soldiers from the Royal Fencible Americans under the command of Colonel Joseph Goreham.