King George's War was the North American theater of the War of the Austrian Succession, marked by conflict between France and Britain, their colonies, and their Indian allies.
In 1742, Great Britain entered the War of the Austrian Succession as an ally of Austria and an opponent of France and Prussia. War was not formally declared until March 1744, and Massachusetts did not declare war against New France until 2 June. The garrison of Louisbourg immediately raided the British fishing port of Canso and raided Nova Scotia's capital of Annapolis Roal. The British were able to force back the Mi'kmaq and Maliseet besiegers of Fort Anne, and Massachusetts sent supplies and reinforcements to help the fort stave off a French attack. In 1745, British colonial forces took Louisbourg after a six-week siege, but the Wabanaki natives of Acadia responded with a campaign of terror against British settlements in northeast Maine. In 1746, a French expedition to retake Louisbourg ended in disaster due to storms, disease, and the death of its commander Jean Baptiste de La Rochefoucauld, Duke of Anville. Massachusetts governor William Shirley ordered the construction of a chain of frontier outposts along the New York border to defend his colony from Indian raids. On 28 November 1745, the French and Indians killed or captured more than 100 settlers in Saratoga, causing the British to abandon their settlements north of Albany. The French and Indians raided the Hoosac River valley, including an attack on Fort Massachusetts, and they also raided Grand Pre in 1747 and Schenectady in 1748. Around 8% of Massachusetts males died in the fighting of 1745-1746.
The war came to an end with the Treaty of Aix-la-Chapelle, which restored Louisbourg to France in exchange for Britain's recovery of Madras in India; Britain recompensated the infuriated New Englanders with a payment of £180,000. Unresolved border disputes would lead to the outbreak of the French and Indian War a few years later.