The accident has taken place on the southbound carriageway between Junction 19 (Knutsford) and Junction 18 (Middlewich / Holmes Chapel).
It is believed to have happened at around 10.45am this morning (Sunday August 16).
Two cars are involved.
All lanes reopened at 11.05am, but residual delays of 25 minutes remain.
There is queuing traffic for three miles.
An Inrix spokesman said: “Queueing traffic for three miles due to earlier accident, two cars involved on M6 Southbound from J19 A556 (Knutsford) to J18 A54 Middlewich Road (Middlewich / Holmes Chapel).
“Travel time is around 25 minutes. All lanes have been re-opened.
“All lanes reopened around 11:05, residual delays remain.”
We’ll bring you further updates on this incident as we get them.