There are several riding options on the island. The easiest and most popular route is the White Rock Bay loop. Other rides include Split Rock Bay (doubletrack but with brutal climbing), Elephant Head (intermediate singletrack), East Side, (singletrack above the eastern shoreline), and Lakeside (singletrack with sections of extremely techy rock).

The mountainous south end of the island (seen on the left of the picture) is mostly dark highly-metamorphosed rock such as quartzite and schist from the Precambrian Era (3.5 to 0.5 billion years ago), while the north end is sedimentary rock such as Tufa, a conglomerate laid down by prehistoric Lake Bonneville. In between there's a band of lighter-colored quartzite -- about half a billion years younger than the Precambrian rock. The transition from light rock (for example, the quartzite in the photo below) to dark rock is abrupt.

In mid to late spring, you'll find plenty of biting bugs on Antelope Island, especially where the trail runs near the shoreline. Douse yourself liberally with bug repellent -- or be prepared to ride very fast without stopping. When taking the photo at left, I ventured about 50 feet off the trail, and was covered in mosquitoes before I could snap the picture.

There's camping at Bridger Bay and White Rock. White Rock provides direct access to all the west-side trails. For non-riders, there are picnic tables and nice swimming beaches with bathrooms and shaded picnic areas on the north end of the island. The visitor's center can sell you a Coke or a T-shirt, or teach you about the history and geology of the island.

Antelope Island functions as a game preserve. Drones are not allowed. Among the wildlife in this nature preserve are 900 bison. The big guys aren't usually aggressive, but they are wild, and they are dangerous. And they're definitely BIG. Don't get close during the calving or breeding seasons.

The Lakeside Trail is an excellent challenge for skilled rock-riders. Intermediates can still enjoy the trail by walking their bikes through the tough sections. There are 3 miles of curving single-track beginning at the campground at Bridger Bay on the far north end of the island, and extending to the White Rock Campground on the west side.

North (Bridger Bay) trailhead GPS N 41° 02.394' W 112° 15.727'. South (White Rock Bay) trailhead GPS N 41° 01.669' W 112° 15.060'.

The middle mile of the ride is insanely rocky and rates an "expert" in technical difficulty, but you can easily hike through the areas that make you nervous. You can ride the trail as an out-and-back, or head overland on the paved roads to make a loop.

One of my favorite rides is an 18-mile out-and-back starting at Bridger Bay. After doing Lakeside, I head south past the campground to the Bone Road trail and climb to Elephant Head. There's around 1200 vertical feet of climbing. Nice views and enough techy riding to satisfy.

The White Rock loop starts at the backcountry trailhead south of the White Rock campground. The lariat loop is 6.5 miles with around 600 vertical feet of climbing. This is the least techy ride on the island, so it attracts the most riders.

The "old" White Rock loop included doubletrack that is now the Bone Road trail. This doubletrack is the main horse route on the island. Not that there's anything wrong with that. Just expect some loose surface and horse poop on Bone Road.
The southeast corner of the White Rock loop has a doubletrack connector to southern Bone Road for those who are continuing to Elephant Head or Split Rock.

On a short side-trip from the middle of the White Rock loop, climb up to Beacon Knob. Impressive views 360 degrees!

Split Rock is a 5 mile doubletrack that descends from the ridgeline east of Elephant Head to the shoreline, then climbs back out. The route isn't really techy, it's just steep. You'll climb a steep hill to get to the loop, then climb an even steeper hill to get back out once you drop down to Split Rock.

To reach the Split Rock loop, head out the backcountry gate. Now choose your route. You can take either of the two limbs of the White rock loop (then the connector trail), or the shorter Bone Road trail. When the connector trail meets Bone Road, head south up the grunt-of-a-hill to the ridgeline.
Just a few feet after crossing the ridge, the doubletrack splits. This is the loop. The climb out of Split Rock Bay is easiest when done in the clockwise direction. So after you pass Elephant Head, keep left for the descent.

Elephant Head is an intermediate-tech singletrack that forks off the Bone Road trail on the ridgeline (just before Bone Road descends to the Split Rock loop). It's a 2.8-mile out-and-back to a viewpoint.

You'll climb about 600 vertical on Bone Road to reach the ridgeline where Elephant Head starts. Up-and-down riding adds about 300 vertical feet on the singletrack. There are a couple of tech challenges on the trail, but nothing an intermediate couldn't handle (when outgoing, the one gnarly drop has a ride-around path).

The view from Elephant Head is awesome. If you're doing Antelope Island, this trail is a must-do.

The East Side trail is singletrack curving along the eastern shore of the island. This is a flatter area with views of the Wasatch Front across the flat bay. This trail is still being extended at the south end. To find the trailhead, fork left as you reach the island (near the marina). A tiny ways down the road, at the next fork, you'll find the trail on the left side of the road.

The East Side trail is 11 miles to Fielding Garr ranch with moderate up-and-down riding. It's a fairly strenuous outing, but less-strong riders can turn around at any time. The official end is at the ranch.

The East Side route is not as gnarly as Lakeside, but you will have a few boulder challenges. It's the longest continuous route on the island, with the option of continuing south to the southern tip of the island on doubletrack after passing Fielding Garr ranch.

Getting there:
Just drive I-15 towards Syracuse (south of Ogden, north of Salt Lake City). Exit at the "Antelope Island" sign and turn west (away from the mountains, towards the lake). You'll be on Antelope Drive. Just drive west until you hit the lake. There's a $10 fee (as of 2017) that includes payment to use the causeway over the lake, and your admission to the state park. With payment of the fee, you can ask for a road and trail map of the island if you need it. Roads are well-marked. Bridger Bay (Lakeside): Keep to the right at every road fork. White Rock: Follow the signs on the main road.