The incident happened around 2:30 a.m. Monday in the 300 block of East Lafayette Street in Norristown.
There, officers found the victim with a head injury.
Investigators initially went on the theory that the person was struck by a vehicle.
However, further investigation revealed the person, who was intoxicated, fell and hit their head.
The person was flown to the Hospital of the University of Pennsylvania.
There was no updated on the person's condition.
The name of the person was not released.