The northbound carriageway was closed between junctions 32 (Broughton) and 33 (Hampson Green) at approximately 2:30am on Friday (June 17).
National Highways said the closure caused delays of up to 90 minutes, with eight miles of congestion, after a lorry carrying diesel overturned.
Police confirmed the driver of the overturned lorry was not injured.
The road was shut for almost 15 hours – reopening at around 5.15pm – while recovery work took place and the road surface was inspected for damage.
“Thank you for your patience today while the lorry was recovered from the scene,” a spokesman for Lancashire police said.
30-minute delays and five miles of congestion remained in the area after the carriageway was reopened.