A 20-year-old man has been arrested on suspicion of arson with intent to endanger life over the Winter Hill fire, police have said.
Lancashire Police said the man, from Wigan, was arrested on Friday morning.
It is the second arrest made by police investigating the fire on Winter Hill as firefighters continue to battle moorland fires which have been raging for days.
Last Friday police arrested a 22-year-old man from Bolton in connection with the Winter Hill moorland fire.
On Friday it was also announced that the army troops sent to help fire crews tackling a blaze on Saddleworth Moor, about 30 miles from Winter Hill, were being stood down.
Around 100 troops from the Royal Regiment of Scotland have been involved in the operation, such as helping to dig trenches in an effort to stop the fires spreading.
But after nine days of assisting local firefighters, the order for military support has not be extended into the weekend.
Beverley Hughes, deputy mayor for policing, crime and fire, said the Greater Manchester Fire and Rescue Service (GMFRS) was making good progress.
A helicopter flyover was carried out on Friday morning to assess the scene and the soldiers were immediately released.
Andy Burnham, mayor of Greater Manchester, also announced on Friday that GMFRS crews will be released from some parts of the incident ground at Winter Hill.
On Saturday the large-scale moorland fires on Winter Hill and Scout Road, near Bolton, merged due to increasing wind speed and a major incident was declared.
Pedestrians and motorists were urged to stay away from the area, with Lancashire Fire and Rescue Service asking people who were offering to help not to head up on to the moors.
Earlier this week, police said the fire, which started on Sunday June 24, was being treated as arson.
Witnesses reported people lighting a bonfire on the moorland above Stalybridge, Greater Manchester, about 50 minutes before the first emergency call to raise the alarm.