Glacial Grooves Geological Preserve

See deep grooves that a glacier scoured into limestone about 18,000 years ago, plus ancient marine fossils

Glacial Grooves Geological Preserve

Kelleys Island, OH, USA
The site is currently CLOSED due to an on-going capital improvement project. The site is anticipated to reopen in September.

Normal hours:
Mon-Sun: All daylight hours
Everyone - $0.00

UPDATE! Due to an on-going capital improvement project, Glacial Grooves is closed to the public. Reopening for full public access is currently scheduled for October 7, 2022.

Masks are no longer required but please practice social distancing whenever possible.


A National Natural Landmark, the Glacial Grooves on the north side of Kelleys Island are the largest easily accessible such grooves in the world and are accessible daily in season, weather permitting, via the Kelleys Island Ferry departing from Marblehead. From a walkway, footbridge and stairs you can look down on the immense grooves, which are 400 feet long, 35 feet wide and up to 10 feet deep, suggesting the tremendous power of the ice that formed them. Average visit time: Allow 30 minutes


Of Devonian limestone, Glacial Grooves Geological Preserve contain marine fossils that are 350 to 400 million years old. They were scoured into solid limestone bedrock about 18,000 years ago by the great ice sheet which covered part of North America.

Glacial Grooves Geological Preserve is locally managed by the Ohio Department of Natural Resources Kelley Island State Parks.

  • Audiences: K-5th Grade Students, 6-8th Grade Students, 9-12th Grade Students, Higher Education Students, Educators, Families, Government, Specialists, Tourists, Community Groups, History Enthusiasts & Sports Fans
  • Historical Topics: Archaeology & Natural History
  • Regions: Northwest Ohio
  • Site Activities: Self-Guided
  • Museum & Site Type: Ohio History Connection Site