This trail is an old one and is also referred to as the Scott Ranch route, which was used by miners and freighters during the Florence gold rush of the 1860s. The Lower Salmon River Trail is all that remains of the Northside River Trail that was used until the CCC constructed the Salmon River Road in the 1930s.
This route is also a section of the historic Milner Trail which provided access during the gold mining days. The trail begins at the second bridge across the Salmon river known as the Manning Crevice Bridge, there is very limited parking here at the bridge, so keep this in mind and make sure not to block the road.
The trail follows the river and has some short ups and downs and there are some challenging rocky spots along the way. The trail also leads to Cave Hot Springs so it is sometimes frequented by soakers. There are some exposed sections along the trail and there is basically no shade, so this would be a brutal run during the summer months in the middle of the day.
Run this trail early or late in the summer or early in the morning, otherwise you might need to dip in the river!