Hike the Ira Spring trail for to the first switchback, then continue straight west on an small unmarked footpath. This is a trail that switchbacks through dark woods until it approaches a stream at around 3400 feet, a little over 2 miles from the trailhead. On the way up avoid two trails that continue west, one of which goes to Dirty Harry's Balcony. When in doubt, follow the trail that goes up!
From the stream a mountaineer's way trail switchbacks up a steepening slope until it emerges in a scree. Now the path becomes considerably steeper and harder to find. It eventually becomes a scramble, and the path is faint and disappears altogether in places. Keep going though, and you will reach a minor peak on the ridge between Mount Defiance and West Defiance with great views. This is a very steep and open south-facing slope.
The optional summit of West Defiance is a few hundred yards west-traverse on the south side of the ridge. On the way down, at around 4600 feet below a stretch of talus, bear right where the ridge splits.
West Defiance - Putrid Pete's Peak

Length
5.0 miles, roundtrip
Elevation
Gain: 3020 ft.
Highest Point: 5220 ft.
Rating
Parking Pass/Entry Fee
Northwest Forest PassWest Defiance - Putrid Pete's Peak
Map & Directions
Getting There
From I-90 east, take exit 45 to Forest Road 6031 and drive to the Ira Spring Trailhead. Be aware that this is a very popular trailhead and can be very crowded in the summer and on weekends.