The River Waring is a small river in Lincolnshire, England, and a tributary of the River Bain. The Waring rises in the parish of Belchford and runs through Belchford village, passing between the villages of Fulletby, West Ashby and Low Toynton before arriving at Horncastle, where it divides Horncastle market place from the part of the town known as Cagthorpe. After the Horncastle floods of the 1960s, the river channel was straightened and its banks built up through the town.