The River Churn is the first tributary river of the River Thames. It rises in the Cotswolds at Seven Springs near Cheltenham, Gloucestershire, England and flows south across the Cotswold dip slope, passing through Cirencester and joining the Thames in the parish of Cricklade in Wiltshire. Its length from source to confluence with the Thames is considerably greater than the Thames from Thames Head. Its flow is also more consistent than the winterbourne Thames, but the Churn is regarded as a tributary historically and therefore by most geography guides. The length of the River Churn is approximately 25 kilometres.