A body was found floating in the Tennessee River across from Ross's Landing on Sunday morning.
The victim is not a competitor from the Ironman competition in which the opening event was a swim in the river, authorities said.
At 8:31 a.m., the Chattanooga Police Department was dispatched to 530 Manufactures Road on a found body.
The age, sex or race of the victim has not been determined.
Investigators are working to find the cause of the incident and identification of the victim.
At this time there is no evidence of a criminal act.