The River Cam is a tributary of the River Great Ouse in the east of England. The two rivers join to the south of Ely at a place called Pope's Corner. The Great Ouse connects the Cam to England's canal system.
The Cam connects Cambridge with the North Sea at King's Lynn, a total distance of about 40 miles (64 km). An organisation called the Conservators of the River Cam was formed in 1702, charged with keeping the river navigable. The Conservators are responsible for the three lockss in and near Cambridge: Jesus Lock, Baits Bite Lock and Bottisham Lock. The stretch above Jesus Lock is known as the Top River, and passes through Byron's Pool and the village of Grantchester. The Top River is open only to puntss and rowing boats. The stretch between Jesus Lock and Baits Bite Lock is called the Middle River, and includes the Backs, which is the most popular section for tourists as it provides good views of several colleges. The stretch north of Baits Bite Lock is called the Lower River.
College rowing teams use the river between Jesus Lock and Bottisham Lock. There are many houseboats in Cambridge on the lower river and a few move onto the middle river during the winter.
In earlier times the Cam was named the Granta. This name is still used for parts of the Top River south of Grantchester. After the name of the Anglo-Saxon town of Grantebrycge had been modified to Cambridge, the river was renamed to match.