Quick FactsOverview
About Mile 16 Hot Springs
Mile 16 Hot Springs, Idaho is a free, undeveloped geothermal spring in the Boise National Forest on Forest Road 474 along the South Fork Salmon River at approximately 4,120 feet elevation. A single pool with a sand and gravel bottom sits close to the river's edge, fed by a natural geothermal spring at around 104 to 110 degrees Fahrenheit. The pool seats approximately four people at shoulder depth and offers open views of the river and surrounding forest. No facilities are on site and access is free.
The spring is named for its location between mile markers 15 and 16 on Forest Road 474 measured from Cascade. It is also known as 16-Mile Hot Springs, Fire Crew Hot Springs, and Sugah Hot Springs. The South Fork Salmon River Road hosts several other natural hot springs within a short drive, including Penny Hot Springs to the south and additional springs extending north toward Yellow Pine.
For those seeking free hot springs Idaho offers with a riverside mountain setting reachable by car, Mile 16 fills a practical role. The paved road reduces the vehicle access issues common at comparable undeveloped springs, though the narrow width requires attentive driving and courtesy to oncoming traffic.
Location & Access
Getting to Mile 16 Hot Springs
Mile 16 Hot Springs is reached by driving 24 miles northeast of Cascade on Warm Lake Road, then turning north onto Forest Road 474 (South Fork Salmon River Road). Continue 16.8 miles to a small pullout on the side of the road, approximately 1.8 miles past Poverty Flat Campground. The pool is accessed by a short scramble down the bank to the South Fork Salmon River. The pullout accommodates approximately two to three vehicles. Parking on the road risks a citation, so pulling fully off the pavement is essential.
Forest Road 474 is paved but narrow, with limited passing opportunities. Drive slowly and use pullouts when oncoming vehicles approach. Standard vehicles can reach the site in good conditions, but four-wheel drive and snow chains or tires are required in winter. Spring runoff can raise the river level enough to submerge the pool temporarily.
For those seeking hot springs near Cascade Idaho along the South Fork Salmon River corridor, Mile 16 is one of several undeveloped options on the same road. No cell service is available along most of Forest Road 474. Download maps before departure and check road conditions for the current season.
The nearest camping is at Poverty Flat Campground approximately 1.8 miles south, and dispersed camping is available along the road within the Boise National Forest. No services are available along Forest Road 474 once you leave Warm Lake Road.
Suitability & Accessibility
Who Can Visit Mile 16 Hot Springs
Mile 16 Hot Springs suits adult visitors and older teenagers who are comfortable driving on a paved but narrow mountain road and who are self-sufficient at a primitive site with no facilities. The short scramble down the bank to the pool is manageable for most people in good physical condition, but the site is not suitable for young children, elderly visitors with mobility limitations, or anyone who cannot navigate an uneven, sloped riverbank safely.
The site is clothing optional, which is the norm at undeveloped hot springs along the South Fork Salmon River corridor. Visitor numbers here are moderate, particularly during the summer fishing season when anglers use the road. Visitors should be comfortable with a clothing-optional environment before arriving.
For those seeking free hot springs Idaho offers in a riverside canyon setting with vehicle access rather than a long hike, Mile 16 fills a practical role. The single pool is intimate and well-suited to a small group or a solo soaker. The views of the South Fork Salmon River from the pool are a notable feature, and the surrounding Boise National Forest offers excellent fishing and wildlife viewing in the same area.
Dogs are welcome at the site but should be kept out of the soaking pool and away from the river's edge during high water. The pool is small enough that an uncontrolled dog could significantly disrupt the experience for other visitors. The proximity to the river is also a hazard for dogs during spring runoff when the current is strong.
Safety & Etiquette
Safety at Mile 16 Hot Springs
Mile 16 Hot Springs requires visitors to be mindful of conditions, as the pool temperature at the natural inflow can reach 110 degrees Fahrenheit and the proximity to the South Fork Salmon River means water level and pool temperature fluctuate significantly by season. Always test the water before entering, particularly in late summer when lower river levels produce hotter conditions. Exit immediately if you feel overheated or lightheaded.
The South Fork Salmon River runs cold and fast during spring runoff. Visitors should stay away from the river's edge outside of the pool during high-water periods. The pool itself can be submerged during peak runoff, making it unusable. Late summer through early fall is the most reliable period for stable pool conditions.
Forest Road 474 is paved but narrow and is the most consistent safety consideration for visitors. The road carries traffic from anglers, campers, and hot spring visitors, with limited passing room in many sections. Drive slowly at blind curves, use pullouts when oncoming traffic approaches, and do not park on the road itself.
No cell service is available on Forest Road 474. Emergency services are based in Cascade, approximately 40 road miles away. Winter access requires four-wheel drive and appropriate winter traction. Carry standard emergency supplies for remote mountain driving on any winter visit.
No facilities exist at the site. Pack out all waste and observe Leave No Trace principles throughout. Open fires near the pool must comply with current Boise National Forest fire restrictions, which can change seasonally.
