Castle Hill, National historic site in Placentia, Canada

Castle Hill is a national historic site on a 103-metre hill above Placentia, Newfoundland, with remains of French and British fortifications. Visible elements include the walls of Gaillardin Redoubt (1692), Fort Royal (1693–1703), a detached redoubt (1697), a British blockhouse (1762), and six smoothbore cannons added in the 1930s. A visitor centre displays exhibits on the fort and the fishing families and soldiers who lived there.

The French erected Fort Plaisance in 1662 to guard their fisheries and the approaches to Canada; British freebooters destroyed it in 1690. Fort Saint-Louis replaced it in 1691, and Fort Royal was added in 1693. Under the Treaty of Utrecht in 1713 France ceded Newfoundland, and the British held the site until abandoning it in 1811.

The site bears traces of both French and British occupation visible in its structures and fortifications today. These layers tell the story of how different powers shaped the same place over time.

The hilltop is reached by walking paths and stairs with viewpoints over the bay and town. A visitor centre with exhibits and a gift shop stands on site, and the ruins of the fortifications lie at the top of the 103 m hill.

Six smoothbore cannons on the site were added in the 1930s, more than a century after the British army left in 1811. Canada Post featured Castle Hill on a 1985 stamp in its Forts Across Canada series, designed by Rolf P. Harder.