What is the longest river in the UK?

The longest river in the UK is the River Severn. It flows for about 220 miles (354 kilometers), running through Wales and England. The river starts in the Cambrian Mountains in Wales and travels through cities like Shrewsbury and Gloucester, eventually reaching the Bristol Channel. The Severn is known for its tidal bore, which occurs at the mouth of the river, where the incoming tide causes a wave to travel upstream. It has historically been vital for trade and transport.