Mill Creek is a great little climbing area in close proximity to Moab. The place is special and feels untrodden even though climbers have been visiting the area for decades. If you choose to visit this little gem, please make sure to treat the area gently. That includes hiking your ass out of the canyon if you have to take a dump!
The canyon is located high in the La Sals and consists of very compact sandstone/quartzite. This lends itself to good face climbing and offers a welcome respite from both the relentless splitter cracks and the hot temperatures of the Moab area. The area is predominantly bolted, but there are trad lines and even the bolted routes often require the occasional gear placement. Bring a light rack and don't leave it on the ground if you're unsure about your climb.
It should be noted that if you are visiting Moab from out of town, Mill Creek is probably not the best destination or rest-day distraction. The area is mostly undocumented, and almost entirely established ground up. Ratings are very stiff, there are often big runouts on non-trivial climbing, and holds are rarely well-chalked and frequently adorned with sand or cobwebs. There is also very little climbing below mid 5.11. Because of the magazines, Mill Creek has a reputation for being Moab's "sport climbing" area, but this is both a disservice to Mill Creek and to climbers as well.
Mill Creek is located midway along the La Sal Loop Road, a scenic drive that runs from Castle Valley up through the La Sals, and back down to 191 just south of Moab. The loop road actually crosses the creek just above the Hydro Crag on an obvious bridge.
The area is actually quite vast, and in keeping with the tradition of the area, it demands a willingness to explore. For that reason, there are no formal guidebooks and other very specific directions are not available here, but with the right attitude and a bit of time, there is a lot of great climbing and adventure to be had. Good luck!
Mill Creek Canyon is indeed a beautiful and special place to climb, however it is worth the while to consider a few important traits of the area before setting out on a visit to MCC.
On an access and conservation note: And these are absolutes... PLEASE drive the speed limit or slower and park carefully and considerately in MCC. This may mean you'll need to walk a bit, but the land manager has concerns about speeding and parking. DO NOT S*&T IN THE CANYON! Walk the 5 minutes up to the road and care for waste disposal in a environmentally friendly fashion!
Climbing: It is wise to understand before going to MCC that it is not in entirety a sport crag - especially in the common (ie. Rifle, Red Rocks) definition of the term (more like Smith's older routes or Tuolome -sp?). Though there are "sport routes" in MCC, more often than not the routes tend to be "sporty" to "run out" - many sport climbers consider routes at MCC to border on terrifying and there are some routes w/ ground fall potential; most have long fall potential, so know before you go. All but about 5 routes in the canyon are accessible from the top and can be previewed or climbed on TR (bring a length of rope to access the anchors from trees). If you can not see bolts all the way to the top of a route, do not assume that they exist, and top rope if you are unsure of your ability or the presence of gear.
It is also wise to carry a small rack to many of the routes as quite a few are "old school", bolts where you need 'em, gear supplementing. In addition, many routes in MCC are harder than they appear (bouldery technical cruxes), so again, if you are unsure, TR. In general, MCC is not a super area for beginners - like most of the dez, for what ever reason, life tends to begin at 5.10 and the easier routes tend to be more run than the harder routes (13a and up). But if you are keen on "adventure sport climbing" do come and give it a try! The area described above is known as "The Wicked Crag" and has some of MCC's finest hard routes.
I'm sorry you're disappointed that my description for Mill Creek doesn't live up to the standards of my other contributions to Mountain Project, but I'm not going to change it and here's why:
First, I should note that I'm not the one who submitted the Mill Creek area - it was a terrible one line description which I adopted in order to actually improve upon. After discussion with locals and other admin-type folks on the site, rather than spell out every detail of Mill Creek, I chose to instead attempt to create something more balanced that would uphold the tradition of the area.
That tradition harkens back to respecting an area and the style in which it was developed, right back to Royal Robbins' vision of climbing during the "golden age" in the Valley. In much the same way you wouldn't retro bolt a classic trad line, spelling out directions to every route in Mill Creek would be a real shame. Rather than call me malicious, you could have contacted me (or anyone else who's climbed there) and asked for more info (as someone did just last week as a matter of fact), which perhaps I could have provided.
As Brendan said, keeping an open mind and sense of adventure and investing a little time and energy in exploring this area will pay back in spades. Spend a rest day hiking from the Wicked Crag out the mouth of the canyon (wear Carharts, trust me), talk to the locals, read the stories in the old mags... I guarantee you'll get a lot more out of the experience. If this isn't your thing, don't worry, the climbing isn't so mindblowing that you're missing out on much - go to Rifle, the climbing is way better, it's closer to Boulder, and you won't have to waste one bit of precious redpointing energy on finding your route.
Josh, I agree with your sentiments...as a former Forest Service employee and new router in the canyon, I must say, that is the nature of this place and it will help preserve it, or it will get over run and get restricted. That said, the climbing is NOT for everyone. There are a few sport pitches around, but it is way more of a cerebral adventure then a day at Rifle. Maybe one of these days I will submit some topos/descriptions for the tons of single pitch lines in the upper canyon and tons of multipitch lines down lower!
it is nice to see that the spirit of mcc is still alive. the place has always been magical. i remember climbing on the sunny side while watching bears forage in the canyon below me. or falcons hunting from the cliff tops. cougars stalking the tree lines of chain drags as we packed out at dusk. any large group of users is a nasty lot. just look at what mountain bikers did to slickrock or indian creek for that matter. if protecting something special means frustrating people who need a guide book to climb, so be it. unfortunately, it is just a matter of time before someone decides their need to make money, or advance their ego will override a concensus of climbers who want to keep something as pristine as possible. it has always been the battle over the canyons ethic. i think it is pretty obvious which side i come down on. as i always told people asking about mcc, you can top rope everything. just bring a pair of jugs.
there used to be lots of juniper and pinion pine trees as well as the accompanying wild life. you didnt have to pay to camp, and when it was developed by the land managers the area was designated as a "national sacrifice area". i am not picking on mountain bikers per se, my point is that any large user group impacts enviromentally sensitive in a negative fashion. i remember having to explain to a group of mntbikers that the tree they just pulled out of the ground for firewood was not "about to die" but had been growing that way for the last couple of hundred years.
go north of Moab, cross the Colorado River take the next main left by the tailings pile, drive about 4-5 miles and you'll see climbs all to the right hand side. Oh wait that's potash.... just go there anyways