Delaware State Police and the state medical examiner have identified the deceased as John G. Heeney, 49, of Delaware City, Delaware.
Dental records were used to make the identification.
Police say there was no obvious trauma and no evidence of foul play.
The medical examiner is still working to determine the cause of death.
It was 10:50 a.m. Wednesday when a billboard maintenance crew found the remains in a marshy area off the southbound lanes of the 100 block of South DuPont Highway (Route 13).
Police told Action News the remains appeared to have been there for some time.
Anyone with information about the discovery is asked to contact the Delaware State Police Major Crimes Unit at Troop 2 at 302-834-2630 Extension #7.