The eastern edge of the parish is formed by a stretch of the North Sea coast from Blackhall Colliery and Castle Eden in the north to Crimdon Dene running through Crimdon Park in the south. This stretch has numerous military sites relating to the defence of the coast during WW2, including practice trenches and pillboxes, but there is also a rifle range on historic maps of the late 19th century. This rifle range was likely in use as a military training site during the First World War and has been noted as disused by 1919.

Inhabitants of the area who served and fell in the Great War and later conflicts are commemorated on various memorials around the parish, including the memorial cross in the Welfare Park of Blackhall Colliery (dedicated to the memory of WW1, WW2, the Korean War and later conflicts), and in St. John's Church at Hesledon.