Ausable Chasm

Ausable Chasm is a sandstone gorge carved by the Ausable River near Keeseville in upstate New York. The river has cut through ancient rock layers, creating narrow passages with sheer walls that tower above the flowing water.

The chasm formed over thousands of years through erosion by Rainbow Falls following the retreat of glaciers after the last ice age. The river continuously carved downward through the sandstone, gradually deepening the gorge into its current form.

The area holds traces of Native American settlements, with historical records indicating conflicts between Mohawk and Algonquian tribes until their departure around 1810.

The site is open from May through October with trails and recreational activities available during these months. Visitors should wear sturdy footwear and check weather conditions before heading out, as rocks can be slippery near the water.

The canyon walls hold preserved trace fossils and ripple marks that reveal this was once an ancient seabed from hundreds of millions of years ago. Some rocks contain rare jellyfish fossils that document early marine life.