Sunflower Flat Hot Spring

Wilderness river soak: Sunflower Flat Hot Spring is a real, public, Forest Service camp spring on the Middle Fork of the Salmon River, reached only by a permitted float or on foot. This page records what the registries and the Forest Service document, and keeps this spring separate from the hotter Sunflower Hot Springs about a mile downstream, a different spring with a similar name.

Sunflower Flat Hot Spring takes its name from the flat it rises on: a small riverbank bench on the Middle Fork of the Salmon River, at the float camp the Forest Service river guide lists at mile 32.6, inside the Frank Church River of No Return Wilderness in Custer County. The federal thermal springs list carries the spring at a maximum of 109 °F on the Greyhound Ridge quadrangle, at 44.733, -115.018, and the U.S. Geological Survey sampled it on June 27, 1980, on the same wilderness survey swing that sampled its registry neighbors.

The Forest Service guide describes the camp’s spring in the plainest and best sentence anyone has written about it: a magnificent hot spring that cascades to the river’s edge, where many floaters stop for the natural shower. There is no road to this reach of the Middle Fork, and there never has been. You arrive the way everyone arrives, by raft or on foot, which is exactly how the camp has always been used.

Read the temperatures on this page the way the record gives them. The 109 °F figure is the federal registry figure; the state geothermal dataset carries the same vent at 116.6 °F, and the federal GEOTHERM file holds both lineages under two record numbers, a split the state dataset’s own notes trace back to the 1980 survey tables.

Nobody has published what the pools at the camp run, and this page does not guess. What the record does support is the shape of the place: a terraced, cascading spring at the edge of an assigned float camp, in the middle of one of the most floated wilderness rivers in the country.

One name note, because the Middle Fork uses this name twice: this is not Sunflower Hot Springs, the 149 °F spring about 1.3 miles east, a separate federal record with its own GNIS entry and its own hotter water. Surveyors and at least one state dataset have used the Sunflower Flat name for both springs at different times, and river people swap the names loosely. This page covers only the camp spring at mile 32.6, the one the federal list carries as Sunflower Flat Hot Spring.

Soak Stats

Place Information

Location and Access

Two ways in exist, and both are expeditions. By river, the spring is a stop on a permitted Middle Fork of the Salmon float: trips launch at Boundary Creek or fly in to Indian Creek, and Sunflower Flat is one of the Forest Service’s assigned camps, a small camp listed at capacity 8 persons in the forest’s campsite appendix. Your party soaks here because the river brought you here, on the second or third day of a five or six day trip, and the permit system that governs the Middle Fork applies to the whole journey, not to the spring itself.

By foot, the Middle Fork River Trail parallels the river for most of its length, and backpackers reach this reach from the Thomas Creek airstrip country and its river bridges, walking the canyon trail to the camp. Josh’s own access note for this spring is the shortest accurate summary on record: MF Salmon River, float or backpack.

The season is set by the river and the snow. The float season in practice runs from late spring, when the runoff drops, through the fall, and the trail approach belongs to the snow-free months. High spring water reaches riverbank springs first, and a cascading spring at the water’s edge is a different place at flood stage than in August; no source documents this vent’s month-by-month state, and this listing claims none. Watch for poison ivy on the climb from the river to the pools, a standing warning in the river guides for this stop.

The Soak

The Forest Service’s own words carry this section, because they are nearly all the verified description this vent has. The river guide calls it a magnificent hot spring that cascades to the river’s edge and notes that many stop here for the natural shower; the forest’s waypoint file calls the camp’s spring terraced and cascading. A 2022 trail-running account of a soak here, under this name, describes multiple soaking pools about 10 feet above the river and a steamy waterfall dropping to the water, which matches the Forest Service’s shape if not its restraint.

Beyond that, the honest record stops: no pool count, depth, or temperature for this vent has ever been published, and the famous, detailed descriptions of pools and showers under the Sunflower name belong in part to the hotter spring downstream, which this page does not borrow from. Expect a handmade wilderness arrangement, hot water falling over rock at a small camp, shared with whoever the river delivers that day, and test any pool before settling in: the source figures on record run from 109 °F up, hot enough to scald undiluted at the vent.

History

The spring enters the written record through the geothermal surveys, in a single busy week. In late June 1980 a USGS party worked this reach of the Middle Fork, sampling Sunflower Flat and Thomas Creek Ranch on June 27 and the hotter Sunflower Hot Springs on June 28, and the registries have carried all three ever since.

The survey-era tables behind those registries were less careful than the party was: a Mitchell (1980) table called both Sunflower vents by the one name, and when the state geothermal dataset later untangled them, its compiler wrote the confusion into the record itself, noting that there appear to be two different springs, 1.3 miles apart, and numbering them 1 and 2. This spring is number 1.

The human history is the camp’s. Sunflower Flat is one of the assigned camps that organize a Middle Fork float, the small right-bank camp at mile 32.6 where a party of eight can tie up under the spring. The Forest Service guide scolds visitors who used soap under its shower, in the direct way of older river guides, which tells its own story about how long and how heavily this spring has been loved by floaters.

Who first improved the terraces, and when, no source consulted records. That is the documented history: a survey spring with a float camp, a shower the guides praise in one sentence, and a name it has had to share.

Nearby Hot Springs

The nearest full listing is Pistol Creek Hot Springs, another documented Middle Fork corridor spring about 10 straight-line miles west, reached the same way, by trail or by permitted float. Downstream and up the corridor are the corridor’s classic float soaks, Sheepeater Hot Springs and Trail Flat Hot Springs. About 0.9 miles southeast sits the registry point for Thomas Creek Ranch Hot Spring, a hotter record on paper and a documentation listing only, with no documented public access; it is a neighbor on the map, not a second soak on the same stop. More East-Central Idaho hot springs →