Sinks Canyon State Park
The Middle Fork Popo Agie plunges into fractured Madison Limestone at the Sinks, then returns downstream at the Rise by a route that dye tracing proved—but still has not fully mapped.
Artwork inspired by Hans Kleiber
At the Sinks, the Middle Fork Popo Agie disappears beneath a ledge of Madison Limestone. A 1983 U.S. Geological Survey dye test confirmed that this water reaches the Rise about 3,500 feet downstream: the leading edge arrived after two hours, and the dye continued clearing through the system for roughly six more. That proves the connection without reducing the underground route to a simple tunnel.
The Rise adds another puzzle. During the test, substantially more water emerged than entered at the Sinks, and its temperature had increased—evidence that groundwater or another stream joins the hidden flow. Visit both viewing areas and compare the churning disappearance with the broad, calm pool where unusually large trout hold in protected water.
The hydrology is only the canyon's first layer. Sagebrush at the lower end gives way to pine and fir as the road climbs toward the Wind River Range, while limestone and dolomite walls draw climbers and river-side trails offer a slower look at the transition. The compact state-park stops are easy to combine; longer hikes continue onto adjoining public lands and demand a separate check of weather, trail, and seasonal road conditions.
- Dye arrival
- Leading edge in 2 hours
- Bedrock
- Madison Limestone
- Visitor center
- Memorial Day–Labor Day
Quick guide
- First question
- Water returning warmer and in greater volume at the Rise
- Set beside it
- The contrast between sagebrush lower canyon and coniferous slopes above ↔ Fine layering and solution openings in the pale Madison Limestone
A focused visit to Sinks Canyon State Park
- Start at the Sinks
- Use the visitor-center exhibits and viewing deck before following the water downstream.
- Then find the Rise
- Compare the calm trout pool with the turbulent disappearance upstream.
- Read the experiment
- Two-hour dye arrival proves a connection, not a straight underground pipe.
- Extend the visit
- Use the 1.4-mile Sink to Rise trail or continue higher only with current conditions.
Good to know
Treat the Sinks and Rise as two connected observations, not one roadside photo stop. The Rise pool and adjacent river section are closed to fishing; remain on the viewing structures and never enter the Sinks cavern or cross barriers around fast water.
Notice these
- Water returning warmer and in greater volume at the Rise
- The contrast between sagebrush lower canyon and coniferous slopes above
- Fine layering and solution openings in the pale Madison Limestone