The longest river in the United Kingdom is the River Severn. Spanning about 220 miles (354 kilometers), it flows through Wales and England, emptying into the Bristol Channel. The river has significant historical and geographical importance, marking the border between England and Wales for portions of its course. The River Severn is renowned for its tidal bore, which occurs as the tide rises and creates a wave that travels upstream. It also supports various ecosystems and recreational activities, including kayaking, fishing, and walking along its scenic banks.