Grantchester is a village and civil parish on the River Cam or Granta in South Cambridgeshire, England. It lies about two miles (3 km) south of Cambridge.

The River Cam is the main river flowing through Cambridge in eastern England. After leaving Cambridge, it flows north and east before joining the River Great Ouse to the south of Ely, at Pope's Corner. The total distance from Cambridge to the sea is about 40 mi (64 km) and is navigable for punts, small boats, and rowing craft. The Great Ouse also connects to England's canal system via the Middle Level Navigations and the River Nene. In total, the Cam runs for around 69 kilometres (43 mi) from its furthest source to its confluence with the Great Ouse.