Narrow Water Forest

The castle ruins at Narrow Water stand right where the Newry River narrows before flowing into Carlingford Lough, and it's one of those spots that stops you mid-stride. Built in the 13th century as a Norman stronghold, the fortress guarded the strategically important waterway between what's now Northern Ireland and the Republic. What remains today is substantial enough to give you a proper sense of scale - the keep still stands with its defensive walls intact, rough stone that's weathered centuries of Irish weather.

Walkers get the most from this one. The surrounding forest creates a lovely circuit, and you can loop back along the water's edge where the views open up across the lough. It's not a strenuous trek, which makes it manageable with older kids or anyone less keen on scrambling. Allow an hour to explore the ruins and another forty minutes or so for the woodland paths if you're not rushing.

There's no visitor centre or facilities to speak of - you're essentially getting archaeology for free, which is brilliant value. Spring and early summer work best, when the forest floor isn't boggy and the light's decent for photographs. The ruins themselves photograph well from the water side, especially if you catch it around late afternoon.

It's easily combined with Kilbroney Caravan Park, just 4.5 miles away near Warrenpoint. That location gives you solid access to the Mourne Mountains walks as well, so Narrow Water fits neatly into a wider exploration of the area rather than being a standalone destination.