Tees, River, is a river in northeastern England. It rises in Cumbria among the Pennines and flows southeast via the towns of Middleton in Teesdale and Barnard Castle, to the busy industrial centers of Stockton-on-Tees and Middlesbrough. The Tees then swings northeast, and the river flows into the North Sea at Teesmouth. The total length of the Tees is about 70 miles (112 kilometers). It is navigable as far as Stockton.
