Smith Cabin Hot Spring

What to expect

Smith Cabin is one of the smaller and less reliable soaks on the Middle Fork Boise River, the long gravel corridor between Arrowrock Reservoir and the old mining town of Atlanta. Some guides call it Smith’s Cabin Hot Springs. It is not a single pool. Hot water comes out in three separate places along the river, at about 3,600 feet, and what you find depends on the river level and on whether anyone has been there with a shovel.

The three seeps sit like this:

• The road-side seep is on the same bank as the Middle Fork Boise River Road. This is the one most people check, because you can reach it without getting your feet wet in the main channel.
• The second seep is across the river and slightly upstream.
• The third seep is about 100 yards upstream of the second. Unlike the other two, it comes out about 20 yards up the bank rather than at the waterline.

Because the first two are right at river level, any pool is just a ring of rocks and sand where hot water mixes with the cold river. Each spring, runoff floods them and scatters the walls. Soakers rebuild them later in the summer, so the pools tend to exist from about late summer into fall and then disappear again.

Set your expectations low. The Idaho hot springs directory that has visited several times found a couple of half-usable pools on the road side in 2006, enough only for a short foot soak, and no soaking pools at the two springs across the river. On a later visit the writer could see pools across the river but did not ford to test them. Some years you will find a decent sit-down pool. Some years you will not.

Temperatures are not fixed. A hot springs directory gives the source as roughly 143°F62°C, and another figure attributed to NOAA data puts it near 138°F59°C. Either way, the water at the seep is scalding, and the soakable temperature depends entirely on how much river water the pool lets in. The water is clear and has no noticeable smell.

There are no facilities at the springs: no toilet, no trash can and no signs.

Getting there

Smith Cabin is in the Boise National Forest, on the Middle Fork Boise River Road (Forest Road 268), also signed as the road to Atlanta.

• From Boise: Drive northeast on State Highway 21 toward Idaho City and take the turnoff for Arrowrock Reservoir near Lucky Peak. Follow FR 268 east past Arrowrock Dam and a string of Forest Service campgrounds. The Forest Service puts Troutdale Campground about 33 miles up the road. Smith Cabin is about half a mile past Troutdale, on the river side of the road.
• From Atlanta: Come west down the Middle Fork road. Loftus Hot Spring is about a mile before Smith Cabin, and Troutdale Campground is just beyond it.

The Forest Service describes FR 268 as narrow in places and rough, and says it is generally passable by car in good weather. Long-time visitors describe it as badly washboarded. Allow far more time than the mileage suggests, fill up in Boise, and carry a full-size spare. There is no cell signal, so save directions and an offline map before you leave the highway.

Park well off the road at a pullout and pick your way down the bank to the river. For the two springs on the far side, you have to ford the Middle Fork. Only do this in late summer or fall when the river is low and slow, wear shoes with grip, and turn back if the water is above your knees or pushing hard.

When to go

August to October is the realistic window. Runoff has dropped, soakers have had time to rebuild pools, and the river is low enough to read. Troutdale Campground is open until the end of September in most years.

Spring and early summer are usually a write-off here. High water covers the seeps and the ford is dangerous.

Winter is possible because FR 268 stays open, but the road can be snowy and icy and the river-level pools are often a mess of ice and mud. Bring a high-clearance 4WD, chains and a partner, or pick a spring closer to the pavement.

Fire season: In September 2026 the Boise National Forest issued a Crooked Fire closure order for several roads and trails in the Idaho City Ranger District through December 31, 2026. The roads it lists do not include FR 268, but conditions change during fire season. Check the Boise National Forest alerts page before you set out.

Rules and etiquette

• Free. There is no fee and no permit.
• Swimsuits required. A Boise National Forest order prohibits public nudity on all forest land from August 27, 2025, to August 27, 2030. Smith Cabin is on forest land and in sight of the road.
• No soap or shampoo, biodegradable or not. These are tiny pools with no outflow other than the river.
• Build, do not wreck. If you rebuild a pool, use loose river rock and sand and leave it for the next person. Do not dig into the bank.
• No glass. Bring cans or plastic.
• Pack out everything, including food scraps and toilet paper.

Where to stay nearby

• Troutdale Campground is about half a mile west. The Forest Service lists it as a free campground with fire rings, picnic tables and a vault toilet, but no drinking water. It is open from the end of May to the end of September unless snow closes it earlier. Horses and pack animals are not allowed. Trail #130 to Bald Mountain starts nearby.
• Primitive sites: There are good undeveloped riverside sites close to the springs and more along the length of the Middle Fork. Bring your own water and pack everything out.
• Other campgrounds: Several more Forest Service campgrounds sit along FR 268 between Arrowrock and Atlanta.
• Boise and Idaho City have the nearest full range of lodging and supplies.

Safety notes

• Scalding source water: The seeps come out far too hot to touch. Feel every pool with your hand, and keep children and dogs well clear of the source.
• The ford: The Middle Fork Boise is a real river. Do not cross in runoff, after storms, or alone. Unclip any pack straps before you start.
• Footing: Wet river rock is slick and the bank is loose. Wear water shoes or sandals with straps.
• Remoteness: No cell signal and long distances to help. Tell someone your plan and your return time.
• The road: Washboard gravel, blind curves and dust from other vehicles cause more trouble than the springs do. Drive slowly and stay right.
• Wildlife: Deer and elk use the river corridor. Store food in your vehicle at night.

Nearby stops worth adding

Smith Cabin works best as one stop on a Middle Fork hot springs day rather than a destination on its own. About a mile upstream, Loftus Hot Spring has two hillside pools fed by a hot waterfall right above the road, and it is far more dependable. A few miles downstream toward Arrowrock, Sheep Creek Bridge Hot Spring is a small roadside seep by the Sheep Creek bridge. Farther up toward Atlanta come Browns Creek Hot Spring, Dutch Frank Hot Spring and Granite Creek Hot Spring. If you have only one afternoon, check Smith Cabin on the way past and keep driving if it is underwater.