The Helford River is a ria in Cornwall, England, fed by small streams into its many creeks. There are seven creeks on the Helford; from west to east these are Ponsontuel Creek, Mawgan Creek, Polpenwith Creek, Polwheveral Creek, Frenchman's Creek, Port Navas Creek, and Gillan Creek. The best known of these is Frenchman's Creek, made famous by Daphne du Maurier in her novel of the same name. A little further up river is Tremayne Quay, built for a visit by Queen Victoria in the 1840s which she then declined to make, allegedly because it was raining.

A ria is a coastal inlet formed by the partial submergence of an unglaciated river valley. It is a drowned river valley that remains open to the sea.