Fort Dunree, Military museum on Inishowen Peninsula, Ireland.

Fort Dunree is a military fortification on the Inishowen Peninsula that sits on a headland overlooking Lough Swilly. The site contains gun emplacements, underground bunkers, and a museum that presents the history of the location.

Fort Dunree was built around 1812–1813 as part of the fortifications defending Lough Swilly during the Napoleonic Wars, opposite Knockalla Fort. Neglected after 1815, it was armed with seven 24-pounder guns in 1874 and remodelled in 1895 with two 4.7-inch QF guns below and 12-pounder and two 6-inch guns in an upper land battery. It stayed under British sovereignty as a Treaty port until 3 October 1938, when it was ceded to Ireland.

The Irish name An Dún Riabhach means 'Grey Fort', though a second derivation, Dún Fhraoigh, gives 'Fort of Heather'. The museum displays restored guns including a BL 6 inch Mk VII naval gun, and exhibitions on the area's birds, marine life and coastal vegetation. The handover ceremony of 3 October 1938 was watched by only a dozen spectators.

The site is laid out with marked pathways that guide you across the grounds and connect different sections. The paths are often exposed to weather and wind, so sturdy footwear and a windproof jacket are sensible choices.

The last territory ceded to Ireland was handed over here on 3 October 1938, when Sergeant O'Flynn of the Royal Artillery lowered the Union Jack and Sergeant McLaughlin of the Irish force raised the tricolour; the two were brothers-in-law. The Times noted only a dozen spectators at the ceremony.