The B6221 is a short link between the A56 to the north of Bury town centre and the A58 to the east.
Starting from traffic lights on the A56 Walmersley Road, the B6221 heads generally southsoutheast through a partly residential but mostly light-industrial area. After passing a larger factory on the left we arrive at a signalized junction of five roads. Here we cross the B6222, our route turning obliquely left rather than continuing straight ahead.
Now heading southeastward along Wash Lane, which is at first also semi-industrial in character, we eventually reach a more residential area after crossing the B6219. The route ends at further traffic lights on the A58 Rochdale Road, where traffic leaving the B6221 must turn left. (Drivers wishing to turn right can make use of the roundabout immediately to the east – junction 2 of the M66 – to double back.)