Not a huge bouldering wall, but fun area nonetheless if want to get in an hour or so of problems.
Good for practicing footwork, traversing, downclimbing, etc.
Max height of rock face is about 13 feet or so and about 25 feet in width.
Access Hollow Trail from main Parking lot and follow until reach junction with Little Yellow Trail. Take Little Yellow Trail and will see the Main Wall on left as trail heads uphill...If don't see it at first you'll eventually be standing ontop of it.
Mountain Project's determination of some of the classic, most popular, highest rated routes for Main Wall: