Fort Amherst is a neighbourhood in St. John's, Newfoundland and Labrador. It is located at, on the southern side of the Narrows, the entrance to St. John's harbour. Apart from some family dwellings, Fort Amherst consists of a man-made harbour, a lighthouse and the remains of gun emplacements and pillboxes built during World War II to defend against German U-boats. Two QF 4.7-inch B Mark IV* guns remain in place, and can still be seen on their mountings.
The original fortifications at Fort Amherst, built in the 1770s, are no longer visible. The fortifications were named for William Amherst, who successfully recaptured St. John's from French forces in 1762. The site was designated a National Historic Site of Canada in 1951.
The name is shared with Port La-Joye / Fort Amherst in Prince Edward Island and Fort Amherst in England.
The first lighthouse in Newfoundland was built at Fort Amherst in 1810. The current lighthouse was built in 1951.