Officers have stepped up their presence at Denaby Crags after a woman was attacked there on Friday.
It is the latest incident at the spot which was the scene of a string of previous attacks in 2014 and 2015. Police say they are not yet sure if the latest incident is connected to those reported there in the past.
But officers are appealing for information, as well as advising women and girls to avoid walking in the area alone.
Officers say the latest incident happened at around 2.15pm on Friday, January, 13.
They say they had a report that a 29-year-old woman was walking alone on Denaby Crags when an unknown man assaulted her, dragging her to the ground. The woman suffered minor head injuries.
Police say the suspect was then believed to have run away from the scene towards Peake Avenue. He was said to have had his face covered.
Detective Chief Inspector Jade Brice from Doncaster Police said: “I completely understand that incidents of this nature are concerning for the local community and I wish to reassure the public that we are treating this incident incredibly seriously.
“We have increased our patrols and I would ask that any members of the public out walking in the area take extra care and report anything suspicious to police.