FATMAP difficulty grade
This is a popular loop in the Boise foothills, close to downtown and easily accessed.
It's on multi-use trails that are loved by walkers and bikers as well, so runners should be mindful of other traffic. The loop mapped here goes up Lower Hulls Gulch Trail, briefly uses Motorcycle Trail to connect with Crestline Trail, then goes down Kestrel Trail.
This direction is preferred by most because the gulch is a more gradual climb than Kestrel, and because views are best when looking out over Boise from Crestline Trail.
Either direction is good, though, and the network of other trails makes variations possible. The trails are for the most part smooth, but in Hulls Gulch you'll find sandy spots and rocky sections––just enough to keep things interesting.
Crestline and Kestrel are nothing but hardpack highways, with wide open views over the grassy hills.