This is an OHV area and the trails can be rutted, eroded, and there can be quite a lot of traffic; not always awesome for running.
Early season (even into June) can have closures from water. Check with the Ranger Station before heading out.
Mill Canyon #40 is a scenic and challenging route that ascends from the American River to the Ridge Trail #157
Start by crossing a bridge and then following the creek along the bottom of Mill Canyon. Within the first mile, you'll run through a mix of forest types and see some of Northern Utah's red rock formations.
As the route ascends, it breaks away from the creek on its way to an intersection with Mud Springs. Continue straight and rejoin the creek for a easy section.
The intersection with the Holman Ridge - Cabin Flat #172
trail marks the beginning of some steady and steep climbing through switchbacks to the Ridge Trail #157
The landscape changes drastically towards the upper reaches of the trail as you travel through large stands of fir.