Black Hill Wildlife Management Area
The Black Hill Wildlife Management Area (WMA) is home to a system of singletrack trails. The WMA is located just one mile east of the city of Ephraim. The trails vary from easy cross-country (Rabbit Run) to moderately techy (Quarry) to full-on downhill (Limekiln), with many choices of routes for loop rides.

The terrain varies from dry and rocky juniper slope to grassy meadow. The forest sections provide no overhead shade, so this ride will be hot in mid-summer. The usual riding season will be May through November.
The starting altitude at the trailhead is 5900 feet, with a top altitude on Black Hill of 6400. Depending on your trail choices, you can do very little climbing, or a lot.

The most popular ride for the locals seems to be pedaling to the trailhead from town, then hitting a few easier and intermediate trails for a loop around the mountain, then back into town via the Limekin Hollow dirt road. I've included the singletrack portion of this loop as the first half of my sample ride below.

Getting to the area is simple. Turn east on 100 North (toward the mountains) in Ephraim. Then keep going until you find yourself crossing a cattleguard to arrive at a trail kiosk and parking area. It's 2.7 miles from the center of town.
None of the singletrack trails actually start at the trailhead, at least not as of May 2018. The mish-mash of trails, ATV tracks, and dirt roads is complicated. You'll need a mobile trail app with GPS tracking, or a good map plus a lot of exploring moxie. It really takes all three to navigate this area. Come prepared.

You'll be starting from the southwest corner of Black Hill. To get to the ridgeline rides and downhills of the western slope, you first need to pedal around the mountain. (The east face is push-a-bike steep, suitable only for downhills.)
It's possible to drive around the mountain on the main WMA road if you don't want to pedal. There's no formal trailhead parking there, but you can find a wide spot along the road.

This is a great loop for older kids and beginners. It's 2.7 miles with just over 100 vertical feet of climbing. From the trailhead, veer right on the eastbound doubletrack and pedal gently uphill 0.6 miles. Turn left when you reach the singletrack Rabbit Run. (On the day of my ride, there was a recently-painted arrow on the rocky doubletrack pointing to the trail.)
The trail meanders through meadows, groves of oak, and stands of juniper. You'll play with a couple of washes on the downhill parts.

After finishing the mostly-downhill 1.5 miles of singletrack, you'll hit the main road. (Don't go across the road. The continuing singletrack looks inviting, but it's actually the last bit of a steep plunge from the top of the mountain.)
Turn south (left) on the main dirt road to return 0.6 miles to the trailhead. Or ride Rabbit Run in reverse.

This is for intermediate riders. It's 11 miles with around 600 vertical feet of climbing. Four of those 11 miles are roads -- mostly dirt but with a bit of pavement on the edge of town.
From the trailhead, follow the directions for Rabbit Run as above. But when you hit the road, turn right (north). Go 0.2 miles then veer right on a smaller road that will turn to the east.

A short bit up the eastbound doubletrack, watch for a crossing trail. When you see it, turn left and pedal up to a doubletrack heading north (ATV trail 46). As you approach a fence, drop left downhill on singletrack (Five Streams trail).
Keep left and downhill at the immediate trail fork, then left again after 0.3 miles (These two forks form a loop. If you go right at the bottom fork, you'll find yourself back up at the top. It's a lovely meander, worth doing if you're not in a hurry.)

The trail will cross the main road and head west, then climb up a side-canyon to a line higher on the mountain. Things will get a little techy. Finally the trail rolls out of a small canyon to hit doubletrack.
Now work south and west (mostly south) until you find yourself on the Limekiln Hollow road heading for the outskirts of town. Turn south (left) on 400 East, then at 100 North turn left and retrace your driving path back to the trailhead. (Note: my ride description below and GPS track will send you up the mountain to the Limekiln Hollow DH.)

This is a long-ish ride with around 2800 vertical feet of climbing. The length of the ride depends on which way you decide to return to the trailhead (DH, WMA dirt road, Quarry trail backwards, or loop through the edge of town).

Pedal around the mountain to the southbound doubletrack as above. Find the Cow Run singletrack, forking away south but slightly uphill. Follow it to the summit doubletrack and climb 1.7 miles to the tip-top.
As you arrive at a wide area at the top of Black Hill, look for a path on the north (left) side that quickly turns back to the west. You might not notice it right away. (The big doubletrack heading south is the beginning of the Limekiln Hollow DH.)

The North Rim trail will follow the edge the cliffs, descending to a spot above the quarry before turning and climbing back uphill. As the singletrack ends on the summit DT, you're at mile 11.1 of your ride.
You're 1/2 mile from the top of the mountain. And still a long way from the parking area. You can head back up to the top for a DH option. Or, you can turn south (right) on the summit DT and coast 0.2 miles to catch the Sloppy Nose singletrack on your right. This will descend back down to the doubletrack along the canal, at a point about 1/10 mile north of where you entered Cow Run.

Pedal to the top of the mountain as above. From the wide view area on top, the doubletrack veers right and south downhill. Stay on that main doubletrack and begin descending south. Veer onto singletrack when you see it. At first the singletrack will rejoin the DT, but then will leave the doubletrack for most of the descent.
The DH isn't too techy, and can be handled by experienced intermediates. There's one four-foot ledge drop you can easily skirt to the left. If you see it in time.

At the bottom, you're forced out of a wash and through a gate on doubletrack. Now stop and consider your return options. If you stay downhill and southwest, the Limekiln Hollow road will take you back to the edge of town for a road return. Or if you work your way north-east, there are a couple of options to drop to the main road closer to the trailhead. See the map and my GPS tracks. At this spot, the branching dirt roads in the junipers can be disorienting. If all else fails, put your bike on your shoulder and hike downhill to the road.

Cougar Alley
This trail starts at the same spot as Rabbit Run as a continuation of the doubletrack, but then climbs (very) steeply over a ridge. Expect an ugly push-a-bike -- 250 vertical feet -- before you get to some very nice downhill. On the Quarry Loop, you can substitute this trail for Rabbit Run and a bit of dirt road.

Other south side trails
These trails are narrow singletrack. In general, trails oriented north-south traverse the slope. Trails going east-west will be occasionally steep, but can be climbed with a bit of gearing and determination. Lots of ride combos here.

Rabbit Drop
At the west end of Rabbit Run, you'll find yourself looking across dirt road at a very lovely bit of singletrack. But it gets steep. This bit of trail is only 1/3 mile long, but it has 400 feet of elevation change. You can use it as a cruel grunt push-a-bike to get to the peak quickly, or as a quick plunge back down to the valley if you're in a hurry to get to your car from the top of Black Hill.

Bottom Line!
Very nice riding area. Fun, lots of variety. Good enough to make the drive from the north Wasatch to do it. But the tangle of trails and doubletracks is confusing. (You would not believe the number of miles and total vertical I spent backtracking to figure out this area.) So do your homework, then come prepared with on-trail resources to figure out where you are!

Getting there:  On US-89 in Ephraim, turn east (toward the mountains) on 100 North. Drive until the road turns to gravel, and continue 2.7 miles from the center of town. As you cross a cattleguard, note the parking area and the kiosk to your right. The road straight ahead north is the main WMA road. The smaller dirt road forking to the east is the doubletrack you'll ride to reach Rabbit Run or Cougar Alley.

Water:  none
Bathrooms:  none
Campgrounds:  Ephraim canyon

Other area trails: Flume and Pioneer in Ephraim Canyon, Skyline Drive