{{Use American English|date=February 2025}} {{Infobox river | name = Willoughby Run | name_native = | name_native_lang = | name_other = | name_etymology = <!---------------------- IMAGE & MAP --> | image = Gettysburg, Willoughby Run.jpg | image_size = | image_caption = | map = | map_size = | map_caption = | pushpin_map = | pushpin_map_size = | pushpin_map_caption= <!---------------------- LOCATION --> | subdivision_type1 = Country | subdivision_name1 = United States | subdivision_type2 = State | subdivision_name2 = Pennsylvania | subdivision_type3 = Region | subdivision_name3 = Adams County | subdivision_type4 = | subdivision_name4 = | subdivision_type5 = Township | subdivision_name5 = Cumberland <!---------------------- PHYSICAL CHARACTERISTICS --> | length = | width_min = | width_avg = | width_max = | depth_min = | depth_avg = | depth_max = | discharge1_location= | discharge1_min = | discharge1_avg = | discharge1_max = <!---------------------- BASIN FEATURES --> | source1 = | source1_location = | source1_coordinates= | source1_elevation = | mouth = | mouth_location = | mouth_coordinates = | mouth_elevation = | progression = | river_system = | basin_size = | tributaries_left = | tributaries_right = | custom_label = | custom_data = | extra = }}

'''Willoughby Run''' is a tributary of Marsh Creek in Adams County, Pennsylvania in the United States.<ref>{{GNIS|1191496}}</ref>

Willoughby Run flows southward between Herr Ridge and McPherson Ridge through the Gettysburg Battlefield.

== References == {{reflist}}

== External links == *List of rivers of Pennsylvania

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Category:Gettysburg Battlefield Category:Tributaries of the Monocacy River Category:Rivers of Adams County, Pennsylvania Category:Rivers of Pennsylvania

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