The woman escaped and ran to a nearby home for help after the man put his gun down. Her father then called police.
The student said she parked her car about 7:45 a.m. and was gathering her belongings when the man opened the door, forced her to the passenger side and drove away while pointing the gun at her.
He took her across the Susquehanna River to Enola, parked the car and forced the woman to walk into a wooded area along Conodoguinet Creek, where he tried to force himself on her but she got away, police said.
The man took her car back to the community college parking lot and left it there. He remains at large.
The ordeal lasted about 45 minutes.
The victim described her attacker as a white man between 35 and 50 years old, with a slight build, short reddish hair, a goatee and wire-rimmed glasses.
The college advised students to be alert but said there is no immediate danger. It plans to review its safety and security policies.
Police are trying to determine whether the abduction is linked to a weekend assault in a Harrisburg city park.
Information from: The Patriot-News, http://www.pennlive.com/patriotnews