Willoughby Run
| Willoughby Run | |
| stream | |
| 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.