Hike from the trail from around the parking lot for trail number 9 (harney peak trail head) which takes you around sylvan lake. To the right is the campground boulder (aka the Gil Boulder). Keep following the trail untill you begin to scramble up the backside following the trail. You will come to an opening between the rocks in which you can see sylvan and the obvious island looking boulder slab. Holds a few boulder problems worth checking out if your around.