High Force is a dramatic waterfall on the River Tees near Middleton-in-Teesdale, within the North Pennines Area of Outstanding Natural Beauty.

The entire river plunges 21 metres (70 feet) over a near-vertical precipice in two stages into a deep plunge pool below, making it one of England's most powerful and impressive waterfalls.

The falls were formed where the Tees crosses the Whin Sill, a hard band of igneous rock also seen at Hadrian's Wall. The upper layer is dolerite, which resists erosion and creates the sharp drop.

After heavy rainfall a usually dry right-hand channel fills to produce a second fall; in exceptional floods, water also overtops the central rock section. In harsh winters the falls have been known to freeze into cathedral-like ice formations.

Visitors can reach the base of the falls via a short woodland walk, or approach along the Pennine Way on the opposite bank for elevated views. The Pennine Way route from nearby Bowlees Visitor Centre also passes Low Force, a smaller waterfall downstream.

Artist J. M. W. Turner painted High Force in 1822, and the surrounding Upper Teesdale landscape continues to draw walkers and nature lovers year-round.