The River Bollin is a river in the north-west of England and a major tributary of the River Mersey.

It rises in Macclesfield Forest at the western end of the Peak District before descending the 10 miles through Macclesfield and Wilmslow where it merges with the River Dean . For the following 10 miles (16 km) it defines the southwestern portion of the border between Greater Manchester and Cheshire before merging with the Mersey north of Lymm.