Sinks Canyon

The park literature is precise about what is and isn't known. Dye tests put the underground transit at over two hours for a journey of a quarter-mile — the water is not in a pipe but threading a maze of fissures, possibly taking on other sinks' water on the way. Measurably more water emerges at the Rise than enters the Sinks, a surplus the geology explains by tributary cracks nobody has surveyed because the passages narrow to fissures a diver cannot take.

The cave system repels the usual attempts: stories of scuba parties making the trip are filed by the park itself as tall tales, and the ceiling cracks hold driftwood jammed there by floods that filled the cavern completely. The canyon's walls are Bighorn dolomite warmed by southern exposure — the rock climbing is international — and the moraines date the glaciers: Bull Lake till 163,000 to 93,000 years, Pinedale 22,000 to 19,000.

The rocks run a longer record — formations on the canyon walls date 280 to 500 million years, laid down under ancient seas before the rivers took up the work. The overflow channel logs the flood years: dry most seasons, it carries water only when runoff tops five hundred cubic feet per second, and ceiling fissures still hold driftwood those floods jammed there.

The Rise is where the legend gets fish. The resurfaced water feeds a pool of rainbow trout running eight to twelve pounds — fattened on groundwater that never freezes — and the state's standing rule is look but don't fish: visitors feed them from an observation deck built in 1972.

The canyon became public in installments — state purchases in 1939 and 1953, the Rise and seven acres donated by Pacific Power and Light to Lander in 1963, and in 1971 the bill creating Sinks Canyon State Park was signed — the first park under Wyoming's new Recreation Commission.

The canyon's lore is the modest kind — a river that goes into the ground and comes back with more than it took, on a timetable nobody can map. The documented story is strange enough that the park's own materials are the legend: a watercourse the Crow named for its noise, doing what the name says inside the rock.

The file's verdict: some sites need ghosts; a river that leaves and returns carrying extra water doesn't. The reports here are hydrological, and the state keeps a visitor center to answer them.

The canyon sits in the Wind River Mountains’ eastern slope under split jurisdiction — Forest Service, BLM and the state park share the ground — and the visitor center runs May through September. Swimming is not permitted at the Rise; the trout are the attraction, and the park keeps it that way on purpose.

A river that takes two hours to go a quarter-mile underground and returns with more than it left is the kind of fact the park prints on the brochure — the legend here needed no exaggeration to outlive its tellers.