Getting ThereVIA THE TRAILHEAD PULLOUT ON HIGHWAY 812: The parking lot is located just in from the southern terminus of Yakima Canyon. Come off of Exit 26 on Interstate 82 and then head west. Make an immediate right on Highway 812 and head north all the way into Yakima Canyon. Stay north and 4 miles from where you turned will be a nice pullout to park in which 3 to 5 cars can park. There is a trail to the right and the left and both do meetup slightly higher and merge into the route up Selah Butte.
From the parking area you can either take the gradual left trail or the steep right trail up. They will both merge roughly a hundred feet up. From there it is a well beaten trail for 1500 feet of elevation gain all the way to a large poll that mark the top of the ledge and what looks to be the end of the trail. I assume many stop here but this is clearly not the summit. From there walk to your left roughly 200 feet where you pick up a faint jeep path. Take the Jeep Road as it goes over the crest of the hill and drops 75 feet to a jeep path. On the crest of the hill you will be right at the summit of Selah Butte with all of its cell phone towers. You make a left at the Jeep Path and take it all of the way to the summit towers where a great view of Yakima awaits.
Red TapeThere is no red tape for this hike.
When to Climb
Summer time can be very hot and dry in this region. Weather can be over 100 degrees for days at a time because this area is semiarid. I would avoid hiking in this area unless other areas are going to through an unusual rainy summer storm.
Fall can be very scenic as well. Some of the trees below in the canyon change a very beautiful fall color and make for a good foreground for shots of nearby mountains.
CampingI did not see any rules stopping you if you wanted bivy on the way up. I would strongly advise not to bivy by the cell towers on top because they might have workers working the towers. I would not do it though because I saw two rattlesnakes while I was up there.
There are also a number of developed camping areas off of 812 such as Big Pines Camping Area, and Untanum Creek Recreation Areas. Many of these campsite do have fees when they are open.