Upnor Castle is an Elizabethan gunfort built in 1559 on the north bank of the River Medway to defend both the waterway and the Royal Dockyards at Chatham. Designed by Sir Richard Lee and completed in 1564, it features a stone keep defended by a pointed bastion jutting into the river, with later additions including a curtain wall and ditch. The fortress gained historical prominence during the 1667 Dutch Raid, when Admiral de Ruyter's fleet exchanged fire with castle batteries before burning English warships—an episode that exposed weaknesses and led to Upnor losing its artillery role. Subsequently serving as a naval ammunition depot, the castle now stands as a historic site documenting England's naval heritage.
