Standing 8368 feet tall on the opposite shore of Diamond Lake from Thielsen, this Cascade peak often gets overlooked. But, Bailey has a trail to the summit that doesn't require rock climbing skills and has the best views of Thielsen along with Crater Lake and Shasta to the south and the Three Sisters and Diamond Lake to the north.
The first part of the hike is just a steep trail through forest but once you reach timberline you are treated to a crater 300 feet across that is snowfilled. Right above it is the false summit and once you pass that, you traverse a rock wall along a steep scree path past a window in the rock that frames the view of Thielsen and Diamond Lake. One scramble move onto the ridge and a walk along a cinder ridge and you are at the summit enjoying those views.
Mt. Bailey was originally named Mt. Baldy due to its domed bare summit but according to Bernstein in "Hiking Oregon's Southern Cascades and Siskiyous, " a cartographer misread a surveyor's handwriting and it's been Bailey since.
Of interest - Snowcats take skiers up to the summit in winter for spectacular skiing.
From the west (I-5), you can reach Bailey via either Highway 138 from Roseburg or from Highway 62, then 230 from Medford. From Roseburg it's about 80 miles and from Medford it's about 101. From the east (Highway 97), take the Highway 138 turnoff at Diamond Lake Junction and go west about 20 miles. All roads lead to the southeast corner of Diamond Lake. Take the Diamond Lake Recreation Area turnoff and drive to the South Shore Picnic Area sign. Turn onto Road 4795 1.7 miles just past Silent Creek to Road 300. Turn left there and go .4 miles to a parking area.
One option available to anyone with a 4WD with high clearance is to cut 2.2 miles out of the trail and access the trail higher up. To do this, you access Road 3703 3 miles west of the Diamond Lake turnoff on Highway 230. There is a Snow Park sign there. Take Road 3703 (gravel) for 2 miles to Road 300. Turn right there (rutted dirt and rock) and go about .1 of a mile to "Road" 380. Turn left onto this road and go 1.5 miles to the trail. Note: this road is definite 4WD territory with some larger rocks in it you need clearance over. The road is sometimes gated and there is only a small faint Mt. Bailey Trail sign at the trail. But if you can get here, it makes the hike nicer.
Northwest Forest Pass is required to park at the lower trailhead. Not sure about the upper one, there were no signs. I would assume it is needed there though as well.
July - October
Around Diamond Lake are several campgrounds:
Broken Arrow Campground
Thielsen View Campground
Diamond Lake Campground
I would recommend the Broken Arrow or Thielsen View ones as they are less popular with awesome views.
Diamond Lake Ranger District