The site was strategically important in Acadia, a French colony that included primarily the Maritimes, the eastern part of Quebec, and northern Maine of the later United States.

The threat of Anglo-American invasion of New France was constant, as England tried to establish power in North America, and Acadia was particularly vulnerable to attacks by water.

The de facto border became the Isthmus of Chignecto at the Missiguash River, site of the prosperous Acadian settlement Beaubassin.

[4] As tensions escalated, in 1749 the British erected fortifications in Nova Scotia at Citadel Hill, Halifax, which they founded as a town; and at Fort Sackville, Bedford.

On the north bank of the Missaguash River, Lawrence found French forces under Louis de La Corne, who had orders to prevent any British advance beyond that point.

But Cornwallis eventually sent Lawrence to the Missaguash River with a stronger force and they routed a group of Abenaki and allied Indians led by Father Le Loutre, a French agent provocateur.

Pichon provided accounts of French activities, plans of forts and an outline of the steps necessary for capture, which Lieutenant-Colonel Robert Monckton later used in the attacks.

[10] A convoy of 31 transports and three warships left Boston on 19 May 1755, carrying nearly 2,000 New England provincial troops and 270 British regulars, and dropped anchor near the mouth of the Missaguash River on 2 June.

[11] The next day the troops, under the command of Lieutenant-Colonel Robert Monckton of the regular army, disembarked a few kilometres from Fort Beauséjour.

The fall of these forts settled the boundary dispute in favour of the British and marked the beginning of the Expulsion of the Acadians.

[9] The minister of Marine, Machault, had good reason to believe the forts had been "very ill defended" and Vergor was summoned before a court martial at Quebec in September 1757 but was acquitted.

In the early spring of 1756, a band of Acadian and Mi'kmaq partisans ambushed a small party of New England soldiers' cutting wood for Fort Cumberland, killing and mutilating nine men.

[13] In March 1758, forty Acadian and Mi'kmaq attacked a schooner at Fort Cumberland and killed its master and two sailors.

[12] In October 1761, commander of the fort Roderick McKenzie of the Montgomery's Highlanders went to Bay of Chaleurs to remove the 787 Acadians.

After the end of the Revolutionary War, by which the United States gained independence, the British abandoned Fort Cumberland in the late 1780s.

In 1920 the fort was designated as a National Historic Site of Canada for its significance to French and British history in the country.