The Fatiron is a large flatiron formation just right (North) of the Maiden. It is broken into two pieces. The first piece (Eastern most)is roughly 650 ft long and is steeper that the 350ft Western most piece.
The Fatiron East face route climbs up the center of both pieces and is one of Gerry Roach's top ten Flatiron climbs. The quality of the rock and different types of climbing make it clear why Gerry decided to honor this route with such ranking.
As many of the rocks on the South part of the Flatirons, the approach to the Fatiron is rather long (1:15 Hr- 1:30hr)if you don't get lost and hike at a brisk pace.
Follow the approach directions as for the Maiden. Starting from the South mesa trail hike north to the North fork of the Shadow Canyon trail (next to the open water trough made out of slate)
Hike South West on the North fork of the Shadow Canyon for some 20+ yards and cross north (right) over and across the tallus field of an old quarry. Once across the talus field head West skirting the talus field. Continue up West trying to make out the formatins above you. As the rough trail starts heading South-West towards the Maiden scramble West in between some very large boulders. From here the Fatiron will be looming above you. The start for the East Face route is done from the North gully of the rock.
The first piece of rock you will bump into is really a Flatironette that leans against the East Face proper. You can climb this for a pitch or so or scramble on it's North side up the steepening gully to where the Flatironette ends and the East face begins. Scramble up to the notch in between and begin.
Mountain Project's determination of some of the classic, most popular, highest rated routes for Fatiron:
From the North side of the Fatiron, climb the notch between the flatironette and the base of the Fatiron. Follow left leaning strata for 20 feet to the base of a crack that divides the East face.P1: During the first pitch this crack is shallow and provides little protection. The easier route up the face follows the right side of the crack sometimes wandering as far as 10-20 feet to the right. Climbing the left side is 5.6. Climb past a bulge and set up a belay at a tree in the crack.P2: Continue...[more]Browse More Classics in CO
I recommend scrambling up the east face of the "fatironette" as an approach to the standard east face route. It's aesthetically direct (with great views of the route above), it adds some fun, secure 4th class climbing, and it's probably just as fast as going around up the north side. The only remotely tough move is getting off the ground. From the top of the "fatironette" you need to scramble up a bit of the Fatiron proper to get to the top of the left-leaning strata and the base of the crack. None of this climbing is harder than fourth class. I don't recommend roping up (or even putting on climbing shoes) unless you are really bad with exposure.
I agree that scrambling up the "Fatironette" is great fun! The very first move off the ground is harder than 4th class, but after that, it's a hike. For the approach, we went up the Mesa Trail to Big Bluestem, back left at the next junction (Mesa again?) for a bit toward the N. Fork of the Shadow Canyon trail. We left the SC trail about 20 paces from the junction at the rock water trough and climbed the gully to the right of the Fatiron after skirting the talus field around its lower and right side (as I think Warren has said above). We eventually found a cairned trail - faint in places - that led us right to the base of the climb. This took us 1hr 15min (and we're no speed demons). Don't confuse this with the last part of the approach described under the Maiden; the latter is farther along the SC trail and will take you up between the Maiden and the Fatiron rather than north (right) of the Fatiron which is the correct way to go.
While this can be approached from below, as suggested, beware of doing so to approach the S. Face Routes, "Little Murders" and "Death by Pickies." The "pickies" (small burrs) are so thick along the S face on the lower 1/2 that they are almost impassible. To approace the South face routes, approach via the Maiden, and from the route "Dream Street Rose" go North and slightly uphill through stable talus for 2 minutes to the South face. "Death By Pickes" is just uphill from a point directly across from "Dream Street Rose" and "Little Murders" is perhaps 100 meters further up.