Siege of Louisbourg

Nearly fifteen thousand British soldiers under Major General Jeffrey Amherst encircled and bombarded the French Canadian fortress of Louisbourg, gaining victory over the French after seven weeks. Britain’s success opened up the St. Lawrence River and exposed Quebec, the center of French power in North America, to subsequent British attacks, ultimately resulting in the conquest of Canada.

Summary of Event

Throughout the seventeenth and eighteenth centuries, Britain and France fought a number of wars both in Europe and in their respective colonies. Canada, also known as New France, provided natural resources and a strategic location from which France could launch raids and attacks on land and sea against Britain’s American colonies. In 1713, following the War of the Spanish Succession, France decided to establish an ice-free port in the entrance to the Gulf Gulf of St. Lawrence, Canada[Gulf of Saint Lawrence] of St. Lawrence—the gateway for maritime trade with Canada. Cape Breton Island Cape Breton Island, Canada offered an ideal location, because a port there would both shield Canada and provide a base for privateers Privateers and naval squadrons. Of course, this port, named Louisbourg in honor of the king, was also likely to be a major British target. [kw]Siege of Louisbourg (June 8-July 27, 1758)
[kw]Louisbourg, Siege of (June 8-July 27, 1758)
Louisbourg, Siege of (1758)
British Canada
French Canada
Louisbourg, Siege of (1758)
[g]England;June 8-July 27, 1758: Siege of Louisbourg[1510]
[g]Canada;June 8-July 27, 1758: Siege of Louisbourg[1510]
[g]France;June 8-July 27, 1758: Siege of Louisbourg[1510]
[c]Wars, uprisings, and civil unrest;June 8-July 27, 1758: Siege of Louisbourg[1510]
[c]Expansion and land acquisition;June 8-July 27, 1758: Siege of Louisbourg[1510]
[c]Colonization;June 8-July 27, 1758: Siege of Louisbourg[1510]
Amherst, Lord
Boschenry de Drucour, Augustin de
Wolfe, James
Boscawen, Edward
Pitt, William, the Elder

Louisbourg was to be protected by a complex fortress featuring the “star-fort” design made famous by the French siege specialist, Sebastien Le Preste de Vauban. Vauban’s fortresses depended on heavy artillery mounted atop fortified positions known as bastions. Bastions were placed so that fire from each covered the approaches to the next. Thus any attack on one bastion would be exposed to murderous cross fire from neighboring positions. In a siege on such a fortress, the role of infantry would be secondary to the fire of the artillery.

Though the French referred to the fortress as “the Gibraltar of the North,” Louisbourg suffered from many weaknesses. While the deep-water port was sheltered and ice-free, the harsh climate and the long winters created a sense of isolation that corroded the garrison’s morale. The construction of Louisbourg was particularly expensive. Locally quarried stone was inadequate, so proper stone was shipped in from France, but unscrupulous bureaucrats and contractors defrauded the government, substituting shoddy materials and reselling the imported stone elsewhere. The sand and seawater mix used in the mortar of the walls did not set consistently. Thus, when cannon were fired from some of the bastions, recoil undermined the walls below. An even more significant problem was topography. The town and fortress were too small to extend to hills that overlooked the city, so during a siege, an opponent could mount guns on these hills and fire directly into the port.

In a contemporary drawing, British ships enter Gabarus Bay at Louisbourg, a French stronghold, marking the first days of seven weeks of fighting. Great Britain’s eventual victory and seizure of the strategic fortress marked the beginning of Britain’s conquest and control of Canada.

(Library of Congress)

Louisbourg-based privateers posed a threat to England’s colonial commerce. During King George’s War, known in Europe as the War of the Austrian Succession, New England militia seized Louisbourg, but it was returned to France by the Treaty of Aix-la-Chapelle Aix-la-Chapelle, Treaty of (1748)[Aix la Chapelle, Treaty of] (1748), which ended that war. To challenge French shipping and protect the northern waters, the British in 1749 built a similar port on the east coast of Nova Scotia called Halifax. On the western side of Nova Scotia lived some nine thousand French settlers called Acadians. British colonial officials feared disloyalty among these Acadians, and in 1755 British troops deported the Acadians to scattered locations among the Thirteen Colonies. Many families were separated, homes and property were destroyed, and a legacy of bitterness was created. Those Acadians who avoided deportation soon began guerrilla operations against the British.

When the French and Indian War French and Indian War (1754-1763) began in 1754, British strategists again planned to seize Louisbourg. The greatest strategic problem faced by the British in the operation was that they had to raise the necessary forces and supplies in Britain and the colonies and then transport them to New France. Thus, any British force would face the potential hazards of weather and French naval patrols before it could even reach Louisbourg. In 1756 and 1757, British expeditions were aborted, because large French squadrons sailed to Louisbourg before the British transports left Halifax. These French warships made impossible any British attempt to sail a large fleet of slow, vulnerable transports loaded with men, guns, and supplies. In 1758, however, an energetic new prime minister, William Pitt the Elder, sped preparations for the siege forces and ordered a more successful interdiction campaign by the Royal Navy to isolate Louisbourg. The success of the campaign was abetted by the willingness of the Royal Navy’s Vice Admiral Edward Boscawen to work amicably with the operation’s overall commander, Major General Lord Amherst.

In 1758, only one French squadron was able to evade the Royal Navy and reach Louisbourg. This squadron consisted of 6 ships-of-the-line and 4 frigates, some of which had been partially stripped of guns and crews to accommodate larger cargoes. By comparison, the 127 British transports in Lord Amherst’s assault sailed from Halifax under the protection of Boscawen’s squadron of 23 ships-of-the-line, 18 frigates, and some lighter vessels. The French ships were too greatly outnumbered to be able to sortie against the transports. During the siege, the bulk of these crews and their cannon would be used to augment the garrison—just as Boscawen would lend some of his gun crews and heavy long-range ordnance to Amherst.

The siege lasted seven weeks and began with a British landing in Gabarus Bay on June 8, 1758. As this was the obvious place for a landing, the French had constructed obstacles and stationed troops above the shore. French fire inflicted many casualties and nearly stopped the landing, but near the west end of the bay, grenadiers and light infantry under the command of Amherst’s energetic, able, and young subordinate, Brigadier General James Wolfe, managed to get ashore and outflank the defenders so that they withdrew back to the city. The hasty nature of this retreat effectively surrendered the initiative to the British.

During the following two weeks, Wolfe’s aggressively led forces seized two critical positions, Lighthouse Point—which controlled access to the harbor—and Green Hill—which overlooked the city. Artillery was soon hauled to these positions, and a bombardment began. Using traditional siege techniques, the British began to dig trenches called “saps” toward the city. At intervals, these saps gave way to covered emplacements from which artillery could batter the bastions from increasingly shorter ranges. Heavy British fire soon began to destroy French guns, while the fort’s structural weaknesses enhanced the effectiveness of the bombardment.

The French efforts to break the siege proved ineffective. The garrison commander, Chevalier Augustin de Boschenry de Drucour, had stationed Acadian guerrillas in the area in the hopes that they would disrupt the British camps and siege lines, but colonial rangers and British light infantry kept the Acadians at bay. French sallies, especially a poorly organized attack on the night of July 9, failed to capture or destroy British positions. The French squadron was too small to challenge Boscawen’s fleet, and British guns emplaced on Lighthouse Point effectively closed the harbor. The town was too small to store extensive supplies, so by the end of July, ammunition and food stores were low, while the British supplies afforded extensive barrages. By July 26, British fire had destroyed forty of the fortress’s fifty-two guns and blasted a breach in one of the major bastions. When on July 26 British sailors launched a bold night attack that destroyed two French warships, the garrison’s morale reached its nadir.

Drucour requested terms for surrender. Terms typical for the time were “the honors of war,” which allowed a garrison to surrender but keep its weapons after promising to not fight again for a specified time. Such an arrangement would also allow the town’s populace to remain in place. Amherst, however, demanded full surrender. On July 27, Drucour capitulated. In August, Amherst ordered that the French garrison and civilians be shipped back to France. When the war ended, British engineers blew apart the fortifications and razed the city so that Louisbourg would never again threaten Britain’s American colonies.


The British victory at Louisbourg was pivotal. Although the long siege made an attack on Quebec the same year impracticable, British-occupied Louisbourg both cut off French reinforcements to Canada and provided a springboard for the French and Indian War campaigns of 1759. Success at Louisbourg established Lord Amherst and his aggressive subordinate James Wolfe as the men who would lead Britain to conquer Canada. Britain’s close coordination between its naval and land forces was an achievement that the French were unable to emulate, and without it, France’s colonial holdings proved indefensible. Finally, Amherst’s decision to deport both the garrison and the town’s civilians made it clear that this was a war of conquest, not of negotiation.

Further Reading

  • Anderson, Fred. Crucible of War: The Seven Years’ War and the Fate of the Empire in British North America, 1754-1766. New York: Alfred A Knopf, 2001. Perhaps the best single-volume history of the French and Indian War; indispensable for understanding the strategies and the significance of the siege.
  • Chartrand, René. Louisbourg, 1758: Wolfe’s First Siege. Oxford, England: Osprey, 2000. An excellent study of the siege, based on a number of firsthand accounts from the daily notes of some of the major participants. Features some fascinating photos taken from the reconstructed fortress, which is now a Canadian National Park.
  • Fowler, William M., Jr. Empires at War: The French and Indian War and the Struggle for North America, 1754-1763. New York: Walker, 2005. Narrative account of the war, describing its causes, the incident that touched off the conflict in 1754, and the battles. Places the war in a wider European context.
  • McLennan, John Stewart. Louisbourg: From Its Foundation to Its Fall, 1713-1758. 1918. Reprint. Halifax, N.S.: Book Room, 1979. This reprint of the 1918 edition provides the most comprehensive study of the construction of the fortress and the siege.

Founding of Louisbourg

War of the Austrian Succession

Treaty of Aix-la-Chapelle

French and Indian War

Acadians Are Expelled from Canada

Seven Years’ War

Loyalists Migrate to Nova Scotia

Canada’s Constitutional Act

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Louisbourg, Siege of (1758)