The discovery was made shortly before 5:30 p.m. Monday in the Delaware and Raritan Canal State Park.
The unidentified body is believed to be that of a Hispanic male, between 18 and 25 years old.
The victim appears to have sustained severe trauma about the head, police say.
The cause and manner of death are both pending an autopsy and toxicology tests.
The Hamilton Police Division's Criminal Investigations Bureau and the Mercer County Prosecutor's Office Major Crimes Unit continue to investigate.
Anyone with information is asked to contact the Hamilton Police Division's Criminal Investigations Bureau at (609) 581-4009 or the Mercer County Prosecutor's Office Major Crimes Unit at (609) 989-6292.