Heise Hot Springs
Heise Hot Springs surfaces at 120°F near Rexburg along East Heise Road, carrying some of the most mineral-laden water in Idaho. Chloride levels hit 2,400 mg/L and sodium reaches 1,500 mg/L, making this a genuinely saline thermal source at 5,102 feet in the upper Snake River Plain.
The spring emerges in the broad agricultural valley east of Idaho Falls, where irrigated fields stretch toward the Snake River Range foothills. Cottonwood groves line the river bottoms, and the Teton peaks stand visible to the northeast on clear days. Annual snowfall stays moderate at 47 inches, and the relatively dry climate delivers just under 18 inches of rain. The roadside setting along East Heise Road makes access straightforward.
Heise sits within the eastern Snake River Plain, where the Yellowstone hotspot track left behind fractured volcanic rock that channels deeply heated groundwater. The slightly acidic pH of 6.4 combined with extreme mineral loading, including 430 mg/L calcium and 82 mg/L magnesium, points to prolonged contact with calcium-carbonate formations at depth. This area has attracted bathers since the late 1800s, when early settlers recognized the thermal potential.
Kelly Island Campground lies about 3 miles away along the South Fork of the Snake River, offering first-come-first-served sites with a five-day stay limit. The spring is roadside with minimal walking required. The high mineral content leaves heavy deposits on rocks near the source. Bring towels you do not mind staining, and rinse gear thoroughly after soaking.
Is Heise Hot Springs worth visiting?
Best for
- Hot spring soaking
- Easy day trips
- Overnight camping trips
The water at Heise Hot Springs is slightly acidic (pH 6.4). It is notably rich in calcium (may support bone density and joint health), magnesium (known for muscle relaxation and stress relief), and sodium (supports circulation and skin hydration).
Some links are affiliate links. We may earn a commission at no extra cost to you.
Scenic, semi-developed camping in a cottonwood gallery forest along the South Fork of the Snake River with views of the Snake River Range foothills. Excellent trout fishing along with hiking, boating, wildlife viewing and OHV riding opportunities nearby. Approximate use season: Mid-May to mid/late September. The Kelly Island Campground has no electrical hook-ups and ATV's are not allowed to be ridden in the campground. This site is equipped with a central spicket for water, vault toilets, pul...