The 11-year-old has been seriously injured in a crash in Stanifield Lane, Farington at around 6.30pm yesterday evening (July 28).
Emergency services rushed to the scene and the boy was taken by air ambulance to Alder Hey Children's Hospital in Liverpool for treatment.
A NWAS spokesman said: "We sent a rapid response unit, an ambulance and the air ambulance to the scene of the accident.
"One patient, a young boy, has been taken to Alder Hey Children's Hospital with serious injuries."
The ambulance service said it was unable to provide further details, but did confirm that there were no other casualties.
The road was closed for more than an hour between the junctions with Lydiate Lane and the A582 roundabout towards Lostock Hall.
Bus services had to be diverted, with the Stagecoach 111 rerouting through Centurion way and the 109 service diverted along Wigan Road (A49).
Lancashire Police has been approached for comment.