The bodies, of a man and woman, were found along Exit 57A, the highway's westbound ramp to southbound Route 19, at around 3 a.m. Thursday.
Firefighters found the bodies after extinguishing a burning pile of wood.
The two were pronounced dead at the scene. An autopsy revealed the cause of death was smoke inhalation.
Personal belongings were found, indicating the two lived there for some time.
The fire, which was determined to be an accident, may have been sparked by cooking equipment the two shared.
State Police closed the exit ramp from westbound Interstate 80 to southbound Route 19 as they investigated.