The incident happened shortly after 5 a.m. Saturday in a female student's dorm room in 1915 Hall.
According to Princeton PR, the student said the intruder gained access to the room by walking into the unlocked dorm room.
The student woke up to find someone with their arm around her. She screamed and the intruder ran off, the school's public safety department said in a tweet.
Alert from Public Safety: Student woke up around 5 am, 1915 Hall, to find someone with arm around her. She screamed, intruder ran off.— Princeton University (@Princeton) October 31, 2015
In a secondary tweet, the school's public safety department said the only description of the suspect was someone in a black hoodie.
Public Safety: only description student could provide of suspect was someone in black hoodie.— Princeton University (@Princeton) October 31, 2015
Nothing was stolen and no injuries were reported, officials said.