|Distance:||8 miles (12.9 km)|
|Meets:||M60, M62, A56|
|Old route now:||M60|
|Route outline (key)|
The section of now M60 running between M67 and M63, and the section between Simister and A576 both previously held the M66 number before being renumbered as part of M60 in 1998. The section between Middleton and Denton, although planned as M66, opened as M60 in 2000.
The section of former M66 to the south of Simister was originally allocated the number of M68, but this did not appear on contemporary signage.
Simister Island forms the north eastern corner of the M60 Manchester Outer Ring Road. Opened in 1970 as a standard two level roundabout with provision for an underpass onto the Bury Easterly Bypass (now M66) when constructed, it has since become vastly over-capacity. In 1999 as part of the creation of the M60, the interchange was given free-flow sliproads for all left turns, and the circulatory carriageway was widened to four lanes with colour-coded Spiral Roundabout markings to direct traffic through the newly signalised junction.
Since 2011, the M66 is no longer lit except for the approaches to junction 4.
- The M66 Motorway (Middleton to the Lancashire/Yorkshire Motorway (M62) Section) and Connecting Roads Scheme 1988 - Orders for M60 J18-19
- The M66 Motorway (Manchester Outer Ring Road, Denton to Middleton Section) and Connecting Roads Scheme 1988 - Orders for M60 J20-24