Sheriff Steve Pelton said a man made the discovery around 2:40 p.m. and called 911. The man had been clearing brush from the wooded property that he helps maintain in the 4600 block of Old Hwy 100.
Deputies were able to confirm the remains are human and they appeared to have been there for several months.
Franklin County authorities are in the process of contacting the property owner, who lives in St. Louis.
There is no cause of death, but the investigation is ongoing.
"It's unsettling, but we're going to do due diligence and try to identify who the victim is and try to bring some relief to the family," said Franklin County Sheriff Steve Pelton. "We are working hard on that and hope to come to a conclusion soon."
The remains will be sent to the St. Louis County Medical Examiner’s Office to determine race, gender, and an approximate time of death.