The Hidden Karst Caves of the Tongass National Forest
Beneath the emerald canopy of the Tongass National Forest, a secret world awaits: karst caves, sculpted over millennia into labyrinths of limestone and shadow. These subterranean marvels, tucked along Southeast Alaska’s rugged coast, offer a glimpse into the forest’s ancient heart. With The Boat Company’s small ships, you can explore these hidden gems, guided by naturalists who unlock their geologic and ecological stories.
A Geological Masterpiece
Karst caves form when slightly acidic rainwater seeps through cracks in limestone, dissolving rock to carve caverns, sinkholes, and underground streams. In the Tongass, thousands of these features dot islands like Prince of Wales, where porous limestone meets the forest’s wet climate. Inside, stalactites drip like chandeliers, and subterranean pools reflect faint light. Each cave is a testament to time, shaped over eons by water’s patient artistry.
One of The Boat Company’s onboard naturalists, Christian Desrochers, writes of the feature in the Tongass: “Karst topography refers to the dissolution of carbonate rocks like limestone and marble (usually it is a reference to the subsurface drainage systems that result with these types of bedrock). This also happens to help produce some of our most productive forests (along with ripariant forests where salmons spawn).”
A Fragile Ecosystem
These caves are more than stone—they’re living ecosystems. Bats roost in their cool recesses, blind cave shrimp navigate dark pools, and ghostly ferns cling to walls, thriving without sunlight. These delicate species, found nowhere else, rely on the caves’ stable conditions. Logging, which disrupts water flows, threatens this balance, making protections like the Roadless Rule—championed by The Boat Company—critical. Our 40-year mission ensures these fragile worlds endure.
Experiencing the Caves
Unlike mega-cruises, our 10-12 cabin ships, M/V Liseron and M/V Mist Cove, anchor in remote Tongass coves, granting access to karst landscapes. Guided hikes lead you through mossy forests to cave entrances, where naturalists reveal stalactite formations and rare species. Guests often say entering a karst cave feels like stepping into another world.
After exploring, savor gourmet meals aboard, paired with fjord views and Glenlivet 12, knowing your journey supports the Tongass.
Join Our Mission
For over four decades, The Boat Company has invested over $30 million to protect the Tongass, advocating for policies like the Roadless Rule to shield karst ecosystems from logging. Every cruise fuels this legacy, blending luxury with impact. Ready to explore the Tongass’ hidden depths? Discover our all-inclusive cruises or learn more about our mission at the buttons below.