The Chew Brook begins as a small stream on the western slopes of Black Chew Head, a hill in the Saddleworth Moor and the highest point of Greater Manchester. Travelling westward down the slope it is joined by several other streams, including the Black Chew Grain. After covering a distance of approximately 1km through marshy moor land, the brook empties out into the Chew Reservoir, which was built in 1912 and was the highest constructed reservoir in England (1600ft above sea level), until the Lamaload Reservoir near Macclesfield in Cheshire was completed in 1963. Excerpts from a labourers description of working on the dam at Chew Valley is available in the book 'Navvyman' by Dick Sullivan.

At the western end of the reservoir, the brook emerges down a narrow and steep ravine, curving steadily to the northwest for 2.3km before this time emptying into Dovestones Reservoir. Exiting out of the western end of Dovestones, the brook - now a small river - meanders through the heart of Greenfield village. Chew Brook ends its journey a short distance below Greenfield railway station where it merges into the River Tame

In 1949 A DC3 plane, flying from Belfast to Manchester, crashed in Chew Valley, killing 22 passengers.