Permanent claim record · Mackinac Island, Michigan

Arch Rock on Mackinac Island is a naturally occurring limestone arch rising 146 feet above Lake Huron, formed by post-glacial erosion roughly 10,000 years ago following the retreat of glacial Lake Algonquin.

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Raw value (vault-stripped) {"tags":["arch-rock","mackinac","geology"],"text":"Arch Rock on Mackinac Island is a naturally occurring limestone arch rising 146 feet above Lake Huron, formed by post-glacial erosion roughly 10,000 years ago following the retreat of glacial Lake Algonquin.","category":"nature"}
Predicatetrivia.fact
SubjectMackinac Island, Michigan (place)
As of
StatusVerified
SourceWest Michigan Tourism: Attractions, Landmarks & Regional Highlights — Perplexity Deep Research (March 2026) (trust 6.5/10)
Reference—
Document hashpending evidence-pack link
Provenance chain
Claim ID52650f02-32a4-4afc-a031-844b2f806cc3