Willoughby Run
| Willoughby Run | |
|---|---|
| Location | |
| Country | United States | 
| State | Pennsylvania | 
| Region | Adams County | 
| Township | Cumberland | 
Willoughby Run is a tributary of Marsh Creek in Adams County, Pennsylvania in the United States.
Willoughby Run flows southward between Herr Ridge and McPherson Ridge through the Gettysburg Battlefield.