From U.S. 24 just south of Leadville, turn onto Colorado 300 and cross the railroad tracks. Drive 0.7 mile and turn left onto County Road 11 toward the Halfmoon Creek. After another 1.2 miles, turn right on the dirt road to Halfmoon Creek. Drive on the good dirt road (except for the usual washboard and potholes) for 5.3 miles to the Mt. Massive parking area on the right. Drive another 2 miles on the now rugged, 4WD road to a small junction. Continue straight - do not turn left on Forest Road 110J. If you have 4WD and good clearance, drive another 0.5 mile to the small, marked trailhead on the right.
From the trailhead (Photo #1), walk through the forest on the great trail for 1.25 miles. Leave the forest and weave through bushes to reach a more-open area at 11,200’ where you’ll get your first view of Mt. Oklahoma, to the west - Photo #2. Follow the trail to the other side of a meadow and reach a trail junction at 11,200’ - Photo #3. Turning right would take you up the 14er Mt Massive - continue west on the North Halfmoon Lakes trail. After hiking back into the trees, pass a long rock-slab (Photo #1) to reach a clearing where you’ll get another look at Oklahoma. Continue up to 11,600’ to a flat, rocky overlook - Photo #6. Just after the overlook, it’s time to leave the North Halfmoon Lakes trail - Photo #7. The remainder of your climb will be off-trail.
Hike west into the dense forest and reach the 1st of two stream crossings less than 0.1 mile after leaving the trail - Photo #8. Cross the stream and continue west for another 0.1 mile to reach the 2nd and larger stream crossing - Photo #9. At this point you should be between 11,600’ and 11,700’ of elevation. If you’re above 11,700’ and the 2nd stream crossing has steep rock on the other side, descend a bit before crossing to easier terrain. After crossing, contour southwest for approx. 150 yards before turning right and ascending west up a subtle ridge (still in the forest) that leads to Oklahoma’s southeast slopes. Exit the forest near 11,900’ - Photo #10.
Continue west/northwest past some rock out-croppings (Photo #11) to reach the entrance of a high basin on Oklahoma’s southeast slopes - Photo #12 and Photo #13. Study your map, photos and GPS (if you brought one) to make sure you’re at the high basin and not off-route. Follow a drainage to 12,700’ and locate a steep, grassy slope to your right (north) - Photo #14. Climb the slope (Photo #15) to reach 13,100’ on a ridge, just east of the summit. Turn left (Photo #16) and hike up the easy, talus-covered ridge (Photo #17) to reach the summit - Photo #18, Photo #19 and Photo #20.