King George's War, 1744–48, a war between England and France in eastern Canada. The war, named after George II of England, was the American campaign of the War of the Austrian Succession. The first event was an unsuccessful attack by the French on Nova Scotia, which the British had acquired in 1713.

The British then decided to attack Louisbourg, a strongly armed French fort on Cape Breton Island covering the entrance to the St. Lawrence River. An army of 4,000 citizen-militia, raised in New England, besieged Louisbourg while a British fleet blockaded it. After a two-month siege the fort surrendered in June, 1745.

French fleets sent out in 1746 and 1747 failed to retake Louisbourg. Under the terms of the Treaty of Aix-la-Chapelle in 1748, England returned the fort to the French in exchange for the return of Madras in India.