• Speleothems in Miller's Chapel.

    Oregon Caves

    National Monument Oregon

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  • Haunted Candlelight Tours

    Haunted Candlelight Tours Offered Sunday, October 26 through Friday, October 31, 2014. The tour begins at 4pm and are first come first serve. The tour is limited to 12 people per group. Last regular cave tour will be at 3pm.

Natural Features & Ecosystems

At Oregon Caves National Monument, we observe unique ecosystems above ground in an old-growth forest and below ground in a cave system. These ecosystems blur in what is known as "twilight zones" of caves--the region of the cave where there is an opening to the forest, where light can penetrate the room. We find photosynthetic plants such as mosses in this area. Furthermore, some animals who inhabit cave environment depend on the forest outside for food. As a result, animals such as bats and wood rats are often found inside twilight zones. There exists a deep connection between a forest and a cave as both environments are linked through biology, chemistry, and hydrology.

Did You Know?

Acid dew dissolves the cave wall to make small pock marks.

Carbon dioxide mixes with water that condenses on the wall of the cave to create a very weak acid. Over long periods of time this "acid dew" eats away at the marble walls of Oregon Caves making the cave larger.