Michigan’s Longest Cave Lies Beneath the Upper Peninsula

Where Is Michigan’s Longest Cave Located?

If you're looking for subterranean fun in Michigan, you may have a bit of a drive ahead of you if you want to explore the longest known cave in the state: Hendrie River Water Cave, located in the Fiborn Karst Preserve, about 20 miles inland from Lake Michigan's shoreline in the Upper Peninsula.

Tucked within a 480-acre former limestone quarry turned nature preserve in Naubinway, Michigan, this cave is part underground adventure, part natural science exhibit, and part "please don't fall in that water."

What You’ll See Inside Hendrie River Water Cave

Aaron Bird via YouTube / Canva

According to Michigan Karst Conservancy, the organization that purchased the property in 1987, the cave snakes roughly 1,500 feet, with flowing water along the floor, tight, towering walls, and passages that feel like nature's version of an escape room.

Get our free mobile app

If you're thinking about exploring Michigan's longest cave, just know it ends with a mysterious section called the Goop Loop, and for good reason (you'll be covered with it). Plus, UpTravel.com reports that the cave is home to Michigan's Little Brown Bat and the Northern Long-Eared Bat, which use the cave for hibernation and otherwise relaxing.

Explore the History of the Fiborn Quarry

Aaron Bird via YouTube / Canva

The Hendrie River Water Cave was formed within the limestone and carved by glacial melt thousands of years ago. According to the Family Destination Guide, the remains of the Fiborn Quarry, operating from 1905 to 1936, can also be explored while visiting the Fiborn Kart Preserve.

How to Tour the Cave Safely

Tours are limited and seasonal, so unless you're into wetsuits, helmets, and wading in icy ankle-deep water while wearing a headlamp, you're better off booking a guided tour. If you plan on visiting the cave without a guide, you must obtain written permission from the Fiborn Karst Preserve. Click here for more information.