Idaho Centennial Trail 2025

The Idaho Centennial Trail (ICT) is a 995mile / 1601km route that traverses the state of Idaho South-North, crossing the Bruneau Desert, and a variety of mountain ranges. It’s generally a low- to mid-elevation trail, at least by the standards of the American west. The route was developed in the 1980s by Roger Williams and Syd Tate, and was designated as the official state trail during Idaho’s Centennial year in 1990. There isn’t an official Trail organization, though recently the ITA (Idaho Trails Association) has become the de-facto organization, and a recently-published ICT guidebook has somewhat increased its popularity.

The route is almost entirely on public land, and most of it is on singletrack trail (70%), while the rest is either dirt roads (20%) or paved roads (5%), with the remainder as bushwhacks or stream wading. The Southern Terminus is near Murphy Hot Springs at the Idaho/Nevada border, and the Northern Terminus is at Upper Priest Falls, at the Idaho/Canada border. Between these two points, the trail traverses the Bruneau Desert, the high prairie, the Sawtooth Mountains, the Frank Church (River of No Return) Wilderness, the Selway-Bitterroot Wilderness, the Stateline Trail, and finally the Cabinet Mountains and the Selkirk Mountains near Priest Lake. The trail generally follows waterways, and is seldom on high ridgelines, giving it a very vegetated and wooded feel.

The main challenges of the route both relate to water – either too much or too little. In the Bruneau Desert, there are just 2 water sources in 105 miles, with two 40-mile water carries. The climate gradually gets wetter as one travels north, with the northern half of the trail following perennial creeks where it’s commonly overgrown with lush vegetation. In the Sawtooth Mountains and in the Frank Church, some creeks can become un-crossable due to snowmelt or high runoff. There is a moderate amount of elevation change, though it’s generally gradual. The highest point is in the Lake Ingeborg in the Sawtooths (8920ft / 2720m), and the lowest point is the Clark Fork River (2070ft / 631m), though much of the trail stays between 4000-6000ft (1200-1800m). This map shows the general route of the Idaho Centennial Trail:

(map)

And I’ve also created an overview route in Google Maps (not for navigation!)

This trail should take about 2 months, as I will likely will cover about 20 miles per day, plus some rest days in towns and for resupply. I’ve known about this trail since 2017 when I was at an ALDHA-West event in Idaho, and one of the presenters mentioned it. At that point, there were very few resources for the trail, and I didn’t have the confidence in my navigation skills for a trail that had a reputation for being overgrown and hard to follow.

I’ll hike this trail as part of the Hot Springs Trail, which uses most of the ICT to traverse Idaho. Where the ICT and HST differ, I’ll stick with the ICT alignment, which is generally shorter and has better resupply options. Because almost all of this trail is in dense forest, there will be a higher risk of wildfires. I’ll try to mitigate this risk by hiking Southbound, so I’ll cover the most forested parts early in July, and by the time August arrives I should be in the sagebrush/desert portion of the trail. But there’s always some luck involved too!