A Geologic and Natural History Tour of the Potomac Gorge below Great Falls                                           

Great Falls BW small

Saturday, June 7, 10 AM – 2 PM

WARNING: June crowds may cause delays - we recommend you arrive at park entrance by 9:15 AM to ensure that you have time to pay entrance fee, park, and walk to Visitors Center to join group

Meet outside of Great Falls Park Visitors Center at 9:45 AM

(In case of rain, check this webpage for alternative plans)


The Potomac River Gorge extends 15 miles from Great Falls to Roosevelt Island and crosses the transition region between the Piedmont Plateau and the Atlantic Coastal Plain. The Gorge is one of the longest and steepest fall zones on the Atlantic coast and is considered to be one the most significant natural areas in the Eastern United States. New age data for Potomac River bedrock has helped illuminate the nature of the geologic and flood-related processes that formed the Gorge, indicating that rates of bedrock gorge cutting can be very rapid.

Join us for a guided hike along the Virginia side of the Potomac Gorge below Great Falls to enjoy the breathtaking scenery and to learn about the geomorphic processes that formed the Gorge and the response of this landscape to climatic and sea level change. In addition, commentary will be provided on the cultural and natural history of the Gorge, which is home to rare invertebrates, the bald eagle, fish like the American shad, and over 200 rare plant species.

Tour Guides

  •  Milan Pavich is a geomorphologist who served with the US Geological Service at its Headquarters in Reston, VA for 39 years and is currently a USGS Scientist Emeritus. Milan's research has explored the relations between earth surface processes and climate, including studies across the U.S., in Europe and Australia on chemical weathering, erosion, and sediment transport. He has also researched Quaternary paleoclimate in the eastern U.S., Mississippi Valley and Alaska and pioneered the use of meteoric beryllium-10 for dating soils and landscapes. His current research focus is on understanding landscape response to climate and improving sustainable land use in densely populated areas.
  • Jim Cummins is a biologist and Director for Living Resources at the Interstate Commission on the Potomac River Basin (ICPRB). Jim has played an integral role in the restoration of the American shad fishery in the Potomac basin through his involvement in the installation of a fish passage in Little Falls (Brookmont) dam and his tireless work in the joint ICPRB/USFWS shad re-stocking program. Jim is also an amateur historian with a keen interest in the intersection of history and natural history.


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Great Falls Park
9200 Old Dominion Drive, McLean, VA 22102

Meet outside of Visitors Center. Click here for directions.


Meet outside of the Great Falls Park Visitors Center at 9:45 AM. The hike will begin promptly at 10:00 AM and last approximately two hours. Afterwards, stay for a (bring-your-own) picnic lunch.

What to bring

Please wear appropriate clothing and a sturdy pair of shoes, and bring sunscreen and an ample supply of drinking water for a 2-hour hike. You may find it helpful to print out and bring the hike field guide: The Incision History of a Passive Margin River, the Potomac near Great Falls - click here to download. We invite you to join us for a bring-your-own picnic lunch after the hike.


The registration fee is $5. (This amount does not include the $5 vehicle fee required to enter the park.)




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