The siege of Port Royal (5–13 October 1710), also known as the Conquest of Acadia, was a military siege conducted by British regular and provincial forces under the command of Francis Nicholson against a French Acadian garrison and the Wabanaki Confederacy under the command of Daniel d'Auger de Subercase, at the Acadian capital, Port Royal. The successful British siege marked the beginning of permanent British control over the peninsular portion of Acadia, which had been referred to as Nova Scotia by the British since 1621. It was the first time the British permanently took and held a French colonial possession. After the French surrender, the British occupied the fort in the capital with all the pomp and ceremony of having captured one of the great fortresses of Europe, and renamed it Annapolis Royal.
The siege was the third British attempt during Queen Anne's War to capture the Acadian capital, and it had profound consequences over the next 50 years. The conquest was a key element in the framing of the North American issues in French-British treaty negotiations of 1711–1713. It resulted in the creation of a new colony—Nova Scotia—and introduced significant questions concerning the fate of both the Acadians and the Mi'kmaq who continued to occupy Acadia. The Conquest of Acadia was a foundational moment in the history of the Canadian state—it was a precursor to the British conquest of New France in the middle of the century.