The woman, referred to as "Lake Michigan Jane Doe," is identified as Yarianna G. Wheeler, 19, according to the sheriff's office. She had been living in Chicago but was originally from Bellwood, police said.
Police released a surveillance photo of Wheeler that they said was used to point detectives in the right direction.
"When they saw the image, they knew they were on the right track. From there, they were able to obtain dental records which led to her ultimately being identified," said Lt. Christopher Covelli, Lake County Sheriff's Office.
Covelli said the image was taken on the last known day she was seen alive.
Wheeler's body was believed to have been in the water for no more than seven to 12 days when recovered on August 15.
The sheriff's office had released a sketch of what the woman may look like.
Police said they are investigating the woman's death as homicide after an autopsy revealed sharp force injuries to her body. The official cause of death is still pending.
If you have any information that may help with the investigation, please contact the Lake County Sheriff's Office.