Howlock Mountain is probably the highest Cascade volcano in Oregon that nobody knows about. At 8351 feet, it's basically the same height as Mt. St. Helens. But, while most Cascade volcanoes are singular masses of rock, sand, lava and ash, Howlock sits on a ridge of peaks called the Sawtooth Ridge. This ridge extends mostly north from Mt. Thielsen for several miles. The summit is somewhat of a source of controversy, at least in my research it is. The ridge actually appears to be an east/west ridge on the northern end of a north/south ridge. On maps, there appear to be two summit pinnacles on the east/west ridge closest to where the name "Howlock Mountain" is placed on maps. The easternmost summit is the highest at 8396 feet. The central summit is a sharp pinnacle listed at 8324 feet. However, the actual height of Howlock is listed on all sources as 8351. Not sure which is correct but you might want to tag both summits to make sure.
The easternmost summit is a mound of "Cascade dinner plates". A term used for the type of volcanic rock that hardens in thin sheets and is extremely brittle. It actually sounds like glass breaking when you walk on it. The central summit, the most dramatic peak reminiscent a smaller version of Mt. Washington, while listed as lower, is a tower of these plates and is extremely loose and hazardous to scramble up. There is a shallow notch on the southwest side of it that is scramble-able but beware, it is WAY loose and dangerous. You can also ascend the pinnacle on a less steep, but loose, ridge on its northwest side.
Howlock Mountain from the north appears as a sharp pinnacle in the center, an easy mound on the left and a narrow ridge on the right, snaking it's way north. It is a really neat-looking peak, very complex in appearance. There are no real trails to the summit(s). The Howlock Mountain Trail comes close but ends at the Pacific Crest Trail in the Howlock Meadows beneath the ridge on its west side. The scramble/hike up into the saddle just south of Howlock on the Sawtooth Ridge is a steep hike but is much easier than the way I climbed this (achieving the ridge further south closer to Thielsen and then traveling north along it). When I was there, there was no evidence of human visitation, just some deer tracks. I'm sure there are folks that climb it but the numbers appear to be very low.
The most direct way is to approach from the west at the trailhead right off Highway 138 at Diamond Lake. The trail is 7 miles to its end and then about 3/4 of a mile cross country to the ridge. It appears to be able to be approached from the east at a much closer place by dirt forest roads but it would be completely trailless on mostly flat forests with trees 50-60 feet tall and little chance to triangulate. (You could try to mark you way but you'd need a ton of flags.) The shortest way to approach is actually to take the Tipsoo Peak Trail to the meadows just below the summit and then travel cross country south to join up with the PCT to Howlock Meadows. This approach will save you 3.4 miles round trip and you start 600 feet higher as well.
There is little information out there on Howlock. Thielsen grabs most of the climbers in the area and it's more difficult than the average hiker wants to deal with. The trail is also a popular winter cross country skiing area. It makes for a most interesting and worthy summit though with excellent views of Thielsen, Scott and McLoughlin to the south and Diamond Peak in the north. Mt. Bailey sits just to the east across Diamond Lake as well.
NOT SO SUMMER
From the north (Portland), take I-5 south to Roseburg, OR (exit 124) and then catch Highway 138 east towards Diamond Lake (signs also say to Crater Lake). Take 138 east to a point between mileposts 78 and 79 and turn right at a sign for Diamond Lake Recreation Area. Go .3 miles to the Howlock Mountain Trailhead on the left. Across this road is a Texaco station. I would suggest gassing up before you head out as the station closes early and you don't want to be stranded out here.
From the south (Medford), you can take Highway 62 to 230 to 138. Turn left onto 138 and proceed 3 miles to the turnoff for the Diamond Lake Recreation Area.
From the east (Bend), take Highway 97 to 138, turn right onto 138 and go 15 miles to the junction with 230. Veer right and stay on 138 to the same point 3 miles down.