Its source is on Bleaklow, 3 miles (4.8 km) east of Glossop, from which it flows south through the Grains in the Water bog, then over gritstone below the Alport Castles landslide to Alport Bridge on the A57 Snake Pass route from Sheffield to Manchester, where it joins the River Ashop.

The Ashop flows into Ladybower Reservoir about 2.5 miles (4.0 km) down the valley, which discharges via the Rivers Derwent and Trent to the North Sea.

At its southern end lie the remains of a tunnel constructed to carry water to a planned but unbuilt cotton mill.

[2] The small hamlet of Alport lies on the west bank near the southern end of the river.

There are several components that are used to determine this, including biological status, which looks at the quantity and varieties of invertebrates, angiosperms and fish.