Police have not identified the woman, whose body was spotted floating in the north branch of the river by an unknown party who called 911 to report it about 10 a.m. Saturday.
A police spokesman told the Chicago Tribune extreme cold may have caused the woman's body to freeze. The remains have been transported to the Cook County medical examiner's office where an autopsy will be performed to determine the cause of death.
Prince William mocks Prince Harry, calls Kate 'babykins' in 'hacked' voicemails
North Korea sends threat -- by fax -- to South Korea