Y-Crack Boulder, named for the prominent Y-shaped cleft on it's southern side, is located northeast of Pinnacle Peak proper and accessed from the main hiker trail via a spur climber's trail that takes you to the base of the formation. The impressive Y-Crack route, rated 5.9, is a memorable old school introduction to wide crack climbing. There are also some moderate face routes on the back (north) side of the formation and rappel bolts on the summit.