The River Cherwell is a tributary of the River Thames in central England. It rises near Hellidon, Northamptonshire and flows southwards for 40 miles (64 km) to meet the Thames at Oxford in Oxfordshire.

The Cherwell is the northernmost Thames tributary. It rises in the ironstone hills at Hellidon, 2 miles (3.2 km) west of Charwelton near Daventry. Helidon Hill, immediately north, forms a watershed: on the south side, the Cherwell feeds the Thames, in turn the North Sea