A 25 metre stretch of ground in Sunnyhurst Wood has been cordoned off following subsidence.
The area is along the north side of the wood above the bandstand on the high level footpath and is believed to have been caused by heavy rainfall last week.
An investigation is planned to determine the extent of the damage.
Coun Michael Law-Riding, Blackburn with Darwen Council's executive member for leisure and culture for the council, said: "The torrential rain late last week has triggered the footpath to subside.
"We have cordoned off the affected ground but would ask people using the wood to take extra care and keep children and pets away from the area."
Investigations will continue to determine what is needed to reinstate the path, however the solution is not thought to be simple and may involve significant expense.
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