South Mountain is the southernmost tall peak of the La Sal Mountains of Utah (11817' or 3602m elevation). It is the only named peak of the range south of Forest Road 73 (La Sal Pass road). There are a few sub-peaks - apparently not of enough prominence for official names.
The route recommended here starts from the La Sal Pass area (Forest Road 73). Elevation here is a little over 10,000' (a little over 3048m). From Moab, drive south on Utah Highway 191 a little over 20 miles to the junction with Utah Highway 46 ("La Sal Junction"). Head east on UT46 for ~12.8 miles (passing through the small town of La Sal) to the gravel road signed as "La Sal Pass" (this is County Road 154). Turn north (left) onto this road, and after another 2 miles you will reach Forest Road 73 on the left (west). Another ~7.4 miles on this road will take you to La Sal Pass. There is an un-bridged crossing of La Sal Creek a couple miles into FR 073 - here it is broad and cobbly and should not be a problem for a low-clearance vehicle during low flow periods. During spring snowmelt, call the Moab Forest Service District Office for road conditions.
There is no maintained trail. Recommended beginning point is at the La Sal Pass area - my group started from our campsite at nearby Medicine Lakes. We took ~2.5 hours from there to get to the summit. Although it is not a long hike, a compass & map are recommended since one will be starting in mostly dense woods with rolling terrain, talus & deadfall. Our plan was to head directly south from Medicine Lakes to the east ridge of the mountain, and up. As (longer) alternatives, one can start at Forest Trail #29 trailhead (La Sal Pass road). The trail swings south of the peak, so one will have to know when to go off-trail for the said ridge. To the south, Carpenter or Lackey Basin might be feasible, but again longer and more difficult.
Descent route: recommend a reverse of the above. My party decided to make a loop of it: we descended directly north to a rocky saddle (or arete), topped the next hill (elevation listed as 11290' [or 3441m] on USGS 7.5' topographic map: "Mount Tukuhnikivatz" 1987 edition), and bush-whacked back down a heavily forested slope, through a swampy area, back to Medicine Lakes. The granite rock at the saddle was dangerously loose and prone to sliding.
note starting point in basin below: Medicine Lakes. Visible on spur road off La Sal Pass road.
Easterly view of the Ridge.
Vehicle use and low-impact camping restrictions apply. Contact the Moab Ranger District (Manti-La Sal National Forest), 62 East 100 North, Moab, Utah 84532. Phone inquiries: 435-259-7155.
There are no nearby developed campgrounds. Informal dispersed camping is permitted at La Sal Pass area (including Medicine Lakes and sites further east along Forest Road 73). Please practice low-impact camping and use existing campsites.
"When ideas fail, words come in very handy."