Loftus Hot Spring is a delightful free soak on the Middle Fork of the Boise River in the Boise National Forest — a hidden gem for hot-spring hunters exploring central Idaho's backcountry. Its signature feature is a hot waterfall that cascades from an upper pool into a lower one, so you can pick your temperature.

There are two sandy-bottomed soaking pools right beside the river: the upper pool runs around 110°F, with the water cooling to a mellower ~104°F in the lower pool as it tumbles down. The riverside setting is gorgeous, and being right off the road makes it an easy stop — no hike required.

Access is the main consideration. Loftus sits along the unpaved Middle Fork Boise River Road, roughly 34 miles in from near Arrow Rock Reservoir (reached from Boise via Highway 21 and East Spring Shores Road). The road gets rough and washboarded the deeper you go, so a high-clearance vehicle is strongly recommended, and it's generally safest from about May through September. Look for the spring on the left just past a steel bridge, with a small pullout on the river side.

The soak itself is the payoff. Because the hot water cascades from the upper pool down into the lower one, you can move between them to find your ideal temperature, and the sandy bottoms make for comfortable soaking — a rare luxury among wild hot springs. All of it sits right on the bank of the clear, rushing Middle Fork of the Boise River, so on a warm day you can alternate between the hot pools and a bracing dip in the cold river just steps away. Framed by forested canyon walls, it's about as scenic a roadside soak as Idaho offers.

Loftus is one of a whole string of hot springs along the Middle Fork Boise River Road, which has made this rough, dead-end road a favorite pilgrimage for Idaho soakers. That popularity is a double-edged sword: the springs can get busy on summer weekends and, being free and undeveloped, they've seen their share of litter and trampling over the years. Treat Loftus with care — pack out absolutely everything (including any trash others have left, if you can), keep soaps and glass out of the pools, and be courteous about sharing the limited soaking space with others who've made the long drive in.

Come prepared for a remote backcountry outing. There are no facilities, no cell service, and no help nearby, so carry plenty of drinking water, food, and a full tank of gas, and let someone know your plans. Always test the water temperature before easing in — the upper pool in particular can run hot enough to scald — and watch your footing on the wet rocks between the pools and the river. Bring a towel, sturdy sandals for the rocky access, and layers for cool canyon evenings.

It's free, open year-round, and undeveloped — pack out everything, respect other soakers, and test the water before easing in.