The longest river in Ireland is the River Shannon, measuring 386 km (240 miles). The largest lake is Lough Neagh, Northern Ireland, which is 396 km² (153 miles²) in area.

From PBS - The Shannon is Ireland's greatest geographical landmark and the longest river. It is both a barrier and highway - a silver ribbon holding back the rugged landscapes of the west from the ...

Northern Ireland and Wales. This is the River Severn, the longest river in the UK. I’m in a place called Ironbridge where the River Severn runs through. And later locals Riley and Maisie will be ...