Alien Run has a bit of everything. The Alien Run Outer Limits
extension throws in rocky climbs and plunging downhills. It's a remarkable mix including one of the largest selections of slickrock in New Mexico.
To reach the trailhead, start at the main junction in Aztec where 544 and 550 meet. Drive 4 mi NE on 550. Turn right on 2770. Go east 2.7 mi, then take a left and go north 0.5 miles past a large gas installation. Just beyond a cattle guard, turn right. Go 0.4 miles to the trailhead.
All of these are heavily used gas well service roads that will be messy in wet weather. When driving and hiking in this area watch out for "identified flying objects" -- gas field vehicles moving at high velocity!
The sign at the trailhead shows 5, 10, and 19 mile options. The distance is actually 16 mi, not 19, for Outer Limits. This description will cover the 10 mile loop. It is directional: hike counter-clockwise.
The first section is a nice warmup on a dirt path, swooping in and out of small arroyos just back from the rim of Hart Canyon. Soon you are hiking on a mixture of slickrock and distinct trail.
At 2.3 mi there is an optional "Black Hole" loop that rolls around the convexities and concavities of the canyon edge.
Now the hiking is mostly on slickrock with Moab-style paint arrows. Some are faded or missing so a bit of route finding may be needed.
At 2.9 miles you can turn left and do the 5 mile loop. Otherwise, carry on along the rim.
Alien Run was developed by Al & Deral Saiz of Aztec. Around 3.2 mi you see an example of their design skills. The trail leaves the rim and climbs up a canyon through boulders to reach another level of rim. This terrain change completely alters the character of the trail.
Around mile 4, the alleged "UFO Crash Site" is off to the left somewhere. Cue the "Close Encounters" soundtrack!
At 4.3 mi you reach the Alien Run Outer Limits
option. This is a completely separate loop with very different characteristics.
Turning to the north you leave the canyon rim behind. Now the trail changes to tight and swooping turns among pinons, with occasional sandy sections.