It happened at around 5 p.m. Friday at the Irem Shrine Circus in Wilkes-Barre (WILKS'-behr-ee). The circus wasn't open at the time.
Police say other trainers rushed to the area and were able to calm the elephant. They say the public was never at risk.
It was not immediately clear what startled the animal.
Police Lt. Steven Olshefski says the investigation has been turned over to the Occupational Safety and Health Administration.
An autopsy is scheduled for Saturday.