It is located opposite Abermenai Point, at the south-western end of the Menai Strait, on the coast of Gwynedd, in the parish of Llanwnda.

Situated at the tip of the Dinlle Peninsula, the windblown, north-westernmost point of the Welsh mainland, the fort is cut off twice a day by the incoming tide.

[1] The fort was built in 1775 for a reported cost of £30,000[2][3] (equivalent to £4.5 million in 2023),[4] by Thomas Wynn, then MP for Caernarfonshire and later to become Lord Newborough.

[6] In the late 1780s, the barracks were used to ward off raiding American privateers from the Irish Sea but despite its military history, "no shots have been fired in anger from the fort".

Small two-storey houses that were used as officer and privates' quarters line the flanks,[1] commodious barracks for the Caernarvonshire county militia.