The Bristol Channel is the area of the Atlantic Ocean and River Severn estuary which separates South Wales from South West England, and is named after Bristol, England.
At two of the narrower parts it is crossed by the Severn Bridge and the Second Severn Crossing carrying, respectively, the M48 and M4 motorways.
At low tide large parts of the channel may become mud flats, as the estuary has a tidal range of 15 metres, the second largest in the world. The estuary is an important area for wildlife, in particular waders, and has many protected areas, including National Nature Reserves.