The Green Arch is on the west face of Tahquitz Rock, just to the right of The Open Book. From Lunch Rock, at the top of the trail, continue around the base of the rock to the right. As you hike up and across under the west face you will pass beneath the starts for Finger Tip Traverse, Traitor Horn and The edge. Finally you will arrive under the huge dihedral of The Open Book. To it's right, starting a pitch above the ground, you will see the perfect, clean right facing corner which is The Green Arch.
The first pitch climbs cracks past some fixed pins to a ledge in the base of the dihedral. Scramble up the ledges and climb a hand crack on the right side of the corner at the start, moving up and around to the left passing some fixed pins. 5.10.
The second pitch climbs the dihedral. Most climbers use chimneying technique for the lower part with both feet working features on the right side, and their back on the left. After a few body lengths you are forced to crank on the thin fingers in the corner a stand up into stems to get through the crux. Where the corner begins arching to the right the climbing is airy and exhilarating, with your left foot stepping notches on the fin of the undercut arch and your right on the steep slab. While the old aid line went all the way out to the end of the arch, the free line exits the arch at it's high point and face climbs past 3 bolts to a large ledge with a fixed ancor. 5.11c.
With two ropes you can rappel from here to the ground, or top out easily by joining the last pitch of The open Book. There are new rap anchors at the top of The open Book as well, or you can walk up and find the friction route descent.
Take tiny to medium stoppers, small to medium cams. You won't need any big gear. The crux pitch is often equipped with many fixed pins. I think it's more fun when they are absent (except for the final two,) as the crack takes small stoppers beautifully. One time I led this pitch with my friend Brent Ingram, and clipped three or four pins along the way. When Brent came up to the belay he had the pins clipped to his rack. Always a clown, he responded to my surprised look with "Well, I am supposed to bring up the gear, am I not?" He had removed them easily by hand.
In my opinion The Green Arch, the Vampire, and Magical Mystery Tour comprise a must do "trilogy" of multipitch 5.11 climbs on Tahquitz Rock.. These routes are each physically and mentally challenging, have exposure, and are significant in their history. There are more difficult routes on Tahquitz, such as Le Toit, and more daring one's such as The Edge. But these three classics are not to be missed.
The first free ascent of The Green Arch was done by Rick Accomazzo, John Long and Tobin Sorenson in 1975. This was just a few years after the very first real rock climbing shoes - called E.B.'s - hit the market. It was during these years, from 1972 through '75 that many of the areas classic testpieces were first done, and these three climbers were central to the action.