Cavern Falls is a waterfall on Cascade Creek in San Juan County, Washington, in the Puget Lowland region, with a total height of about 20 feet. It lies about 11.7 miles northeast of Friday Harbor and roughly 17.3 miles southwest of Bellingham as the crow flies.
At 20 feet it is on the modest side for Washington, where the typical waterfall with a recorded height stands around 82 feet; it ranks 851st of 941. The tallest single drop is 12 feet. The water comes down as a tiered waterfall, falling in several distinct steps one after another, combined with a horsetail character. It falls in 2 drops.
The Puget Lowland is a glacially shaped basin of low hills, lakes and wetlands between the Olympics and the Cascades, once covered by Douglas fir and western red cedar and now the most settled part of Washington. Streams here run through terraces of glacial till and outwash, with waterfalls where creeks cut through the deposits. Cascade Creek carries 11 recorded waterfalls; the biggest of them reaches 40 feet.
There are 9 recorded waterfalls in San Juan County. Rustic Falls, a 10-foot veiling plunge waterfall, is under a mile away. Paul Falls, a cascade waterfall, is under a mile away. Cascade Falls, a 40-foot veiling horsetail waterfall, is under a mile away.
Cavern Falls is located at 48.6483° N, 122.8290° W. The listing is based on the World Waterfall Database, one of the sources compiled by the U.S. Geological Survey in its inventory of waterfalls and rapids of the conterminous United States. The creek name is confirmed against the federal Geographic Names Information System. The exact position has not yet been verified on aerial imagery, so treat the map pin as approximate. Details on trails, parking and access have not been documented for this waterfall yet.