The body of water that separates the UK from mainland Europe is the English Channel. This narrow stretch of water lies between southern England and northern France and is approximately 21 miles wide at its narrowest point, known as the Strait of Dover. The Channel has been a significant geographical feature throughout history, serving as a barrier against invasions and influencing trade routes between the two regions. In addition to its historical importance, the English Channel is a popular route for shipping and ferry services, connecting various ports and providing a crucial link between the UK and continental Europe.