Chimney Rock is the apogee and centerpoint of a long, high divide that runs NE-SW between Mt. Daniel and Chikamin Peak in the Central Cascades. The divide is unmistakable and recognizable from many vantages. The peak is eight miles NE of Snoqualmie Pass. There are other peaks along the divide but Chimney has the greatest alpine feel (glaciers and vertical rock on multiple sides). The other peaks on the divide are Bears Breast Mountain, the Summit Chief Massif (Little Big Chief, Middle Chief, and Summit Chief), the Lemah Mountain Massif (Lemahs 1 through 5), and Overcoat Peak (not quite on the divide but close enough to warrant inclusion). The divide acts as a barrier to air flow. Clouds will often butt up against the wall. If their ceiling is high enough, they may spill over the saddles and onto the east side. This was the case the day I climbed Three Queens.
Does Chimney Rock looks like a chimney? Well, yes and no. You need to have a little imagination. Certainly, from the south (say, from Three Queens) it has that appeal, but from the north there is less of a chimney look and more of a long serrate crest much akin to the Picket Range in the North Cascades. The peak was named well before the first ascent in August 1930. In this regard, its appellation is no doubt due to its macroscopic form, not its appearance up close in terms of multiple chimneys of the type rock climbers must stem up.
Chimney Rock is actually a massif of three summits and a lesser summit: Northeast, Main, South, and South Point. The South Point (7,240 + ft), a quarter-mile south of the Main Peak, is not of much interest. The South Peak (7,480+ ft) is an eighth-mile south of the Main Peak. With a steep climb up the couloir between it and the Main Peak, it would be merely a scramble along the crest. I bet it sees very few ascents in a given decade. Perhaps the most astonishing object on the massif is the Northeast Peak (7,634 ft). Its unclimbed South Face alone will make your jaw drop. Untouched sulfurous colored lichen on the face will make you pee in your pants. All in all, that peak looked more appealing from a mountaineering standpoint, but it was not our objective.
There are three glaciers surrounding the Chimney Massif: the Chimney Glacier on the south and southeast, the Overcoat Glacier on the north side, and an unnamed glacier on the east side of the Northeast Peak. The Chimney Glacier features an upper section and a lower section (not much crevassing). Between these a spectacular ice fall drops (can an ice fall plummet?).
Rock is metamorphosed breccia, vertically dipping. In places--near the outlet of the Chimney Glacier, for example--one encounters white sedimentary exposures. It's too bad the peak isn't made of this sedimentary rock, as scrambling over its slabs was very pleasant.
Note: This topo map may be helpful.
There are north side approaches to the peak but I will omit them here (or possibly add them later). Most parties will elect to approach the peak from the south or southeast as the shortest approaches and easiest routes are on this side. Because of the peak's position close to the Cascade Crest, the Pacific Crest Trail runs close by. The trails south of the peak are quite good.
The shortest approach is from the Pete Lake Trail (No. 1323) which starts at 2,800 ft six miles SE of the peak. From I-90, take the exit to Roslyn (Exit 80 if coming from the west; Exit 84 to Cle Elum if coming from the east). Proceed past Roslyn and continue approximately 13 miles past the east shore of Cle Elum Lake to the Cooper River Road (FR-46). In about 4 miles, a junction to the right leads to Owhi Campground and shortly thereafter the Pete Lake Trailhead.
Take the boring and flat trail 4 miles to Pete Lake (2,980 ft). Good camping here though the mosquitos might bug you to death. Continue approximately 1 mile west to where the trail comes to Lemah Creek (a ford continues straight but you want to turn right). Continue north for about 1.5 miles to an old avalanche swathe (c. 3,360 ft) where the Pacific Crest Trail switches back sharply to the right. Look to your left (west) at two waterfalls coming down from a hanging basin. That basin is your objective. To get to it, you'll want to find a climber's path in the steep forested slope right of the falls.
Keep keen for the PCT switchback. Leave the trail at the switchback and continue straight for about one hundred yards to gain the trees beyond. Once in the trees, bear left at an angle toward the creek. Do not follow the swathe-forest treeline to the creek but instead bear deeper into the woods as you approach the creek. You are aiming for a log crossing wherever it may be (i.e., it's not permanent).
Once across the creek, bear due west up steep timber. The climber's path is quite worn in, so you should be able to find it. It is just right (north) of a minor ravine plunging eastward. Pink flagging will also be helpful. At some point the path comes to a promontory with a fire pit in it. You could camp here but you might as well continue on to the basin above. The path crosses three ravines. The first is easy. The second is the hardest. It's a little sketchy and dusty but, with care, you should be able to get into and out of it (green belays may help). The third ravine crossing is easy.
The path then works its way up through light brush then big alder until a final open traverse to the morainal rocks of the hanging basin. Watch for cairns. Once onto the rocks, bear across the basin slightly upward aiming for a gargantuan boulder in the middle near the creek. There are at least three bivy sites around this boulder--the big bivy boulder. In particular, on the boulder's overhung southside, two single-person bivy rectangles make for a premium campsite.
A Trail Park Pass is required for the Pete Lake Trail. You can pretty much expect it to be required for any popular trailhead in the area. Also, the peak and most of the approach are within the Alpine Lakes Wilderness, so standard wilderness policy applies. You can ride a bike for the first 2.6 miles of trail to a junction but that is it.
I once said this to my climbing buddy: "Chimney Rock is a man-mountain not to be trifled with." No doubt my friend was being cocky about casually climbing the peak. Well, you can't casually climb this peak as there is no easy way up it. Every route involves some measure of Class 5.
This is a summer kind of climb. However, early summer is better than late summer. This is because crevassing on the glacier and moats at the base of the rock can become problematic. Water is available year-round in the bivy basin but may require snowmelting on the glacier. By mid-summer, the rock portion of the climb will be dry.
You can camp at Pete Lake, numerous places along the trail, at the firepit promontory on the way to the bivy basin, or in the bivy basin at the southern toe of the Chimney Glacier. Some have even bivied at the summit as there are at least two suitable places there to sleep (not necessarily to pitch a tent, though).
Chimney Rock lies just east of Snoqualmie Pass. It is therefore not far enough east that West-of-Crest forecasts are invalid. I have therefore added both links below: