Lower Loon Creek Hot Spring

Wilderness river soak: Lower Loon Creek Hot Spring is a real, documented stop on Middle Fork of the Salmon River rafting trips, reached by a short hike up Loon Creek. This page records what the registries and the river guides document; no source speaks to conditions this season.

Lower Loon Creek Hot Spring is the soak the river saves for day three: a large, hot pool beside a cold creek, about a mile up Loon Creek from its confluence with the Middle Fork of the Salmon River, at about river mile 50 in the Frank Church River of No Return Wilderness. The federal thermal springs list carries the spring at 120 °F on the Ramey Hill quadrangle

the U.S. Geological Survey’s GEOTHERM file carries it as record 0081110 at the same 49 °C, and the state geothermal dataset records a small cluster of vents at the same spot, 120.2 to 121.1 °F, and classifies the use as undeveloped recreation. The river record agrees with the registries: Middle Fork outfitters count Loon Creek among the six hot springs in the river’s first 52 miles, alongside Trail Flat, Sheepeater, Sunflower, Whitey Cox and Hospital Bar, and call its pool the largest on the river.

One name note, because this creek carries two springs: this is not Upper Loon Creek Hot Springs, a different and hotter spring some 11 miles south on the upper creek, listed separately on this site. This page covers only the lower spring, the river-trip soak above the Middle Fork confluence.

Read the access on this page honestly. There is no road, no campground at the spring, and no casual visit: the Middle Fork runs on a Forest Service permit system, and nearly everyone who soaks here arrives by raft, on the third or fourth day of a wilderness float, and walks up the creek from a river camp. What waits at the end of that walk is the Middle Fork’s roomiest soak and a cold creek one step away, which is exactly the combination the river’s regulars plan their camps around.

Soak Stats

Place Information

Location and Access

Almost every visit starts at Boundary Creek, the Middle Fork’s put-in, reached by forest road from Stanley. Private trips run on lottery-allocated permits through Recreation.gov and commercial trips through licensed outfitters, with the permit control season running from late May through September. Loon Creek comes at about river mile 50, typically on the third or fourth day of the float, and the camps river runners use for the soak (Big Loon at the creek’s mouth, Loon Creek Camp up the drainage, Cow Camp and Shelf Camp nearby) are assigned under the permit system.

From camp, the trail follows Loon Creek up through the wilderness bottom, past a historic ranch and private pasture, across the Loon Creek bridge, and on to the pool. Stay on the trail through the ranch country: the land the path crosses is private even though the country around it is wilderness, and the arrangement works because river parties treat it gently.

Published hike distances vary with the starting camp: about a half mile from Loon Creek Camp, about three quarters of a mile from Big Loon, and a mile to a mile and a half measured from the river itself. Budget an easy half hour each way from a river camp and you will be close.

The land alternative is a long wilderness hike on the Middle Fork Trail, and the Lower Loon Creek airstrip, a backcountry strip about a mile north of the spring operated by the Idaho Department of Fish and Game, puts small planes within a twenty-minute walk of the trail. Outside the float season the canyon is snowbound wilderness; there is no plowed or road access in any season.

The Soak

The pool is the point. Where most Middle Fork springs are bankside pockets, Loon Creek’s is a genuine swimming-sized soak set beside the creek: outfitters call it the largest hot spring pool on the Middle Fork, the river guides put its capacity at roughly ten people, and the airstrip guide at the neighboring strip describes a pool about 10 by 20 feet and 3 to 4 feet deep.

The source water arrives at about 120 °F, hot enough that the pool’s comfort depends on how the creek mixing is running, and Loon Creek itself flows right there for the cold plunge that every account of this spring mentions. Trip reports describe evening soaks under wilderness stars after the rafts are tied off, horses grazing the private pasture on the walk in, and the particular quiet of a hot pool a mile from the nearest boat. It is an undeveloped wilderness soak in every respect: nothing is maintained, nothing is signed beyond the trail, and what you pack in comes back out with you.

History

The spring enters the written record the way most Idaho batholith springs do, through the geothermal surveys: Ross noted the Loon Creek springs in the state Bureau of Mines and Geology’s 1971 geothermal pamphlet, Mitchell and others carried the lower spring into the 1980 state survey at 120.2 °F, and the federal list and GEOTHERM file fixed it at 49 °C under the name Lower Loon Creek.

The state dataset’s working notes preserve a small honest puzzle from that survey era: the federal survey listed two sites on this reach and a third nearby, close enough together that the dataset’s compiler wondered in writing whether there are really three springs, or one spring with a couple of vents.

The human history runs alongside the survey history in the Loon Creek bottom itself: a historic ranch on the trail in, a backcountry airstrip that once belonged to J.R. Simplot and now serves Fish and Game and wilderness pilots, and a river camp tradition that has made this pool a planned stop on Middle Fork itineraries for decades. Who first dammed the pool, and when, no source consulted records; like the bathhouse springs elsewhere in this country, it was already a known soak when the guides started writing it down.

Nearby Hot Springs

The nearest full listing is Hospital Bar Hot Springs, the Middle Fork’s last soak, about 2.6 straight-line miles north near river mile 53. Upriver, Sheepeater Hot Springs and Trail Flat Hot Springs complete the corridor set this listing joins, and the name sibling to the south has its own page as Upper Loon Creek Hot Springs. More East-Central Idaho hot springs →