John Bell says he parked his car Sunday in a remote parking lot, not one blocked by a barrier.
The 56-year-old Bell, of Chadds Ford, says two rangers were waiting with their car lights flashing when he returned.
Bell plans to fight the ticket in federal court. He says he saw many other runners and bikers in the park.
A National Park Service spokesman in Washington, D.C., did not immediately return a call Monday.
A park service release says 20,000 employees have been furloughed, while about 3,000 are providing security and emergency services.
Bell's lawyer, Jeremy Ibrahim, says his client is just trying to stay fit, even as Congress debates a national health plan.