Trinity Hot Springs

## Overview Trinity Hot Springs is a natural geothermal spring located in the mountains of central Idaho, situated at approximately 43.554°N, 115.273°W. The spring lies within the broader Boise National Forest region, an area well known for its abundance of natural hot springs fed by deep geothermal activity along the Idaho Batholith — one of the largest granite intrusions in North America. This geological formation heats groundwater as it circulates deep beneath the surface, producing the warm and hot springs that dot the central Idaho wilderness. While detailed historical and water quality records for Trinity Hot Springs are limited, the central Idaho backcountry has a long tradition of hot spring use, both by indigenous peoples and by miners and settlers who arrived in the region during the 19th century. Many of the area's hot springs have been enjoyed for generations as natural soaking spots in remote, scenic settings. ## Directions 1. From Boise, head east on ID-21 (the Ponderosa Pine Scenic Byway) toward Idaho City. 2. Continue northeast past Idaho City, following ID-21 as it winds through the Boise National Forest. 3. Use the GPS coordinates **43.5540, -115.2731** to navigate to the spring's location, which is situated in a remote area east of the main highway corridor. 4. A high-clearance vehicle is recommended, as access roads in this part of the forest can be rough, unpaved, and seasonally impassable due to snow or mud. 5. Check current road conditions with the Boise National Forest ranger district before heading out, especially in spring and late fall. *Note: These directions are approximate and based on the GPS coordinates provided. Local forest roads may require additional navigation; a detailed forest service map or offline GPS is strongly recommended.* ## What to Expect Trinity Hot Springs is located in a remote, mountainous area of central Idaho surrounded by dense conifer forest and rugged terrain typical of the Boise National Forest. Visitors should be prepared for a backcountry experience — there are unlikely to be developed facilities, signage, or maintained paths at the site. As with many undeveloped hot springs in Idaho, water temperatures can vary and may be quite hot near the source. Exercise caution when entering the water and always test the temperature before soaking. The spring's remote location means you may have the area entirely to yourself, especially on weekdays or during the shoulder seasons. Cellphone service is generally unreliable in this part of the forest, so plan accordingly. Bring adequate supplies, let someone know your plans, and be mindful of seasonal access — many forest roads in central Idaho are closed or difficult to navigate from late fall through early spring due to snow. Wildlife, including bears and mountain lions, inhabit the area, so store food properly and stay alert. The water from geothermal springs in this region has historically been used for soaking but should not be assumed safe for drinking without proper treatment.