About The Sinks and Rise
The Middle Popo Agie River performs a genuine disappearing act inside Sinks Canyon State Park. At a limestone cavern called the Sinks, the entire river rushes beneath the rock and vanishes from sight. It returns at a large pool called the Rise about a quarter mile downstream.
A dye test conducted in 1983 confirmed that the two features are connected, but the results deepened the mystery. The colored water took more than two hours to travel underground, far longer than expected for such a short distance. Researchers also found that more water flows from the Rise than enters the Sinks, indicating that hidden springs or underground channels join the river along its unseen route.
Visitors can view the Sinks from an overlook near the visitor center, then follow the road or walking paths toward the Rise. The pool is home to large trout that gather in the clear water, but fishing is prohibited.
The exact underground passage has never been fully mapped because the narrow, water-filled limestone system is too dangerous to explore directly.
Why it’s weird: A full-size river disappears into a cave, spends hours traveling a quarter mile, and emerges carrying additional water from an unknown underground source.
Visitor info: The park is about six miles southwest of Lander. Access and facilities can vary with weather and season, so check current park conditions before traveling.