The 12th Boat Race took place on a river that is how long?
The Boat Race 1854: The 12th Boat Race took place on the River Thames on 8 April 1854. River Thames: The River Thames ( ) is a river that flows through southern England, most notably through London. River Thames:  At 215 mi , it is the longest river entirely in England and the second longest in the United Kingdom, after the River Severn.
215 mi