The body was found near to Cadzow Glen, Hamilton at around 10.15am on Sunday.
It comes after Amber Gibson, 16, had been reported missing from the Hamilton area on Friday.
The death is being treated as unexplained and enquiries remain ongoing.
Police are asking members of the public who have any information to get in touch.
Chief Inspector Briony Daye said: “At this time, our thoughts are very much with Amber’s loved ones, as they come to terms with this terrible loss.
“As we continue our enquiries, there will be an increased police presence in the area. I’d like to thank the public for their assistance so far and ask anyone with information who hasn’t already spoken with officers to please call 101, quoting incident 1281 of 28 November.”