Valley Forge Fossil Day 2026

Valley Forge Fossil Day on Saturday, October 17, 2026 is a day of interactive, family-friendly activities and special programs. NPS Graphic / G. Purifoy

Celebrating Ice Age Fossils

In honor of the 17th anniversary of National Fossil Day, Valley Forge National Historical Park is celebrating the amazing Ice Age fossils of Valley Forge with a day of interactive, family-friendly activites and special programs.

Learn about mastodons, saber-toothed cats, giant ground sloths, and lots of other incredible critters that walked the ancient landscape of Valley Forge hundreds of thousands of years before George Washington and the Continental Army ever set foot here.

Huh? There are fossils at Valley Forge?

Yes there are!

George Washington and the Continental Army at Valley Forge had no way of knowing in the 1770s that they were camped practically on top of one of the richest fossil sites in eastern North America.

The Port Kennedy Bone Cave (in what is now Valley Forge National Historical Park) was discovered during limestone quarrying in the 1870s and explored through the 1890s. Around 1,200 fossil specimens were removed, including fossilized bones from Ice Age (Middle Pleistocene) mammals like bears, giant sloths, American cheetahs, saber-toothed cats, mastodons, and many more!

Today, most of the fossils are in the collections of the Academy of Natural Sciences of Drexel University in Philadelphia and the American Museum of Natural History in New York.

Learn more >

NPS Photo / G. Purifoy

See Some Fossils!

12 noon to 4 pm in the Visitor Center at Valley Forge

Meet paleontologists from the Academy of Natural Sciences of Drexel University! Explore real fossils, casts of fossils, and how these animals ended up together in what is known as the Port Kennedy Bone Cave.

Click to download the Junior Paleontologist Activity Book. NPS Image

Be a Junior Paleontologist

12 noon to 4 pm in the Visitor Center at Valley Forge

Pick up a copy of the Junior Paleontologist Activity Booklet in the Visitor Center at Valley Forge! Complete the activities in the booklet and show it to a ranger in the visitor center to earn a special Junior Paleontologist badge. (While supplies last!)

Print your activity booklet at home and bring it with you!

Learn more about the Junior Paleontologist Program

Fossil Day Science Talks

An Entrance to Former Worlds: the Cave, Landscape, and Geologic History of Valley Forge

1 pm in the Meeting Room at Valley Forge

John A. Sime, Ph.D.

Lecturer, University of Pennsylvania

This is a story about how five-hundred-million-year-old rocks, which formed beneath ancient seas, came to entomb seven-hundred-and-fifty-thousand-year-old fossils, that recorded the demise of extinct land mammals.

The Fossils of Valley Forge's Port Kennedy Bone Cave

2:15 pm in the Meeting Room at Valley Forge

Jason Downs, Ph.D.

Professor, Delaware Valley University

Have a look inside the collections of the Academy of Natural Sciences to see many of the remarkable fossils from Valley's Forge's Port Kennedy Bone Cave and to learn about the diverse species to which they belong.

The Bone Wars: A Story of Brutal Competition in Early Paleontology

3:30 pm in the Meeting Room at Valley Forge

Liam O'Donnell

Science Educator

Edward Drinker Cope, who analyzed fossils found at the Port Kennedy Bone Cave, is better known for his role in the "Bone Wars," a period of ruthless competition with Othniel C. Marsh that led to lots of underhanded dealings as well as scientific discovery.

NPS Graphic / G. Purifoy

Evening Campfire Talk - Port Kennedy Bone Cave

7 pm at Muhlenberg's Brigade

What was life like in this part of the world 750,000 years ago? Fossils found right here in Valley Forge give us clues! Join us for a discussion about the history of this fossil excavation, and about the Ice Age animals that once made this place their home.

What to Bring: Flashlight, blanket, jacket, camp chair.

Weather: The program will be canceled for rain, call 610-783-1000, option 1 before 5 PM to check on the status of the program.

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