The bodies were found face down in several inches of water in a ditch, said Janet Niedosik, a spokeswoman for the Atlantic County prosecutor's office.
One of the bodies was discovered by two women walking along an access path, and police then found the other three bodies, Niedosik said.
The bodies were "some distance apart from each other," Atlantic County Prosecutor Jeffrey Blitz said.
None were identified by authorities Monday.
A cause of death had not been determined. Autopsies on four women were to be conducted Tuesday, a day after their bodies were found in a ditch behind a budget motel just outside of Atlantic City. Authorities planned to speak to the media sometime in the afternoon, the Atlantic County prosecutor's office said.
WPVI-TV in Philadelphia initially reported that the victims were found shot to death, but later said that was not confirmed.
The spot where the bodies were found is less than 200 yards from the Atlantic City Visitors Welcome Center just outside the city.
Pointing to the area near the motels, which is known for drugs and prostitution, Egg Harbor Township resident Mike Lamkin told CBS station KYW-TV in Philadelphia, "Over there, it's like a whole other world."
Dotted with cut-rate motels, the area has become seedier and seedier in recent years, said Larry Huggup, who stays at the Golden Key Motel, where rooms go for $15 a night.
"It's nothing but drugs, sex and violence. People try to sell you some drugs or ask if you're selling yourself. That's all there is. You can get away with anything out here," Huggup said Tuesday morning.