Piethorne Brook and its feeder streams originate on the area of high moorland at Windy Hill on the south side of the M62 motorway close to its summit near the old boundary between Lancashire and Yorkshire.

The source of the brook, and its immediate feeder stream, is beside Rock Stones Hill, at 415 metres above sea level (1360 ft.), to the south west of the telecommunications mast beside the A672 Oldham-Ripponden road.

The brook has ten other feeder streams including two from Axletree Edge beyond Bleakedgate Moor, which rises to 425 metres (1400 ft), two from Millstone Moss between Green Hole Hill and Readycon Hill, rising at 445 metres (1450 ft.) and flowing down Great Whinning Gulf and Little Whinning Gulf, via Culvert Clough, into Cold Greave Brook.

[6] The brook marked the end of the Shaw to Featherstall (Littleborough) turnpike road after funding from mill-owners in Crompton and Two Bridges was withdrawn.

[7] In the 19th century, the brook was used in the creation of several reservoirs in the area including Norman Hill, Piethorne, Kitcliffe, Ogden, Rooden and Hanging Lees.

[8] One explanation of the brook's name is that "pie" is short for magpie, and "thorne" for hawthorn, both bird and bush re common in the area.

[11] Butterworth, writing in 1828, described the area above Newhey, where Piethorne Brook enters the River Beal; he wrote that "there are many woollen mills, supplied with numerous streams of water".

A stone-step cascade, or man-made waterfall, was built for the brook to pass from Norman Hill into Piethorne Reservoir.