Salmon La Sac sits at the point where the Cooper River comes down out of the west and joins the Cle Elum River, about 19 miles north of Cle Elum in the Okanogan-Wenatchee National Forest. The drive up is State Highway 903, which becomes Salmon La Sac Road, running north out of Cle Elum through Roslyn and Ronald and then along the east shore of Cle Elum Lake. The road reaches the campground at roughly 2,300 feet. This is the last developed spot before the Alpine Lakes Wilderness, and the confluence is the reason people stop here.

The water is straight snowmelt off the high country around Waptus Lake and the Cooper Lake basin. It runs green over pale granite and river cobble, with a string of pools and slower runs stacked between short riffle sections. Some of the pools hold real depth against the rock walls, which is why the spot has a long history of cliff jumping and rope swinging. Depth shifts year to year as high water moves gravel around, so anyone thinking about jumping should get in and check the landing zone first rather than trusting last summer's memory.

Access is easy by swimming hole standards. Roadside pullouts along Salmon La Sac Road put you within a short scramble of the Cle Elum River, and the Salmon La Sac Trailhead at the end of the spur road has a proper gravel lot. That trailhead lot carries a Forest Service day use fee of $5 per vehicle per day, or $30 for an annual Northwest Forest Pass, and Interagency America the Beautiful passes are honored. The trailhead is the only place in the immediate area where you pay to park for the day. Camping is separate. Salmon La Sac Campground charges $27 a night for a single site, $54 for a double and $11 per extra vehicle, with about 40 of its 69 sites reservable through Recreation.gov and the rest first come, first served. The campground runs late May to mid-September and has vault toilets, potable water, fire rings and picnic tables.

Season matters here more than at most places. Through May and June the Cle Elum runs high, fast and genuinely dangerous, pushed by melt from several thousand feet above. It drops through July, and late July into early September is when the pools settle out and the water becomes tolerable. Tolerable is relative. Even in August this is cold enough to shorten your breath on entry, and the shaded pools under the canopy stay colder than the open ones.

There is more here than the swim. The Cooper River Trail #1311 leaves the trailhead and follows the Cooper River upstream through old growth toward Cooper Lake, on a gentle enough grade to work as a family walk or a mountain bike ride, and it passes quieter pools along the way. Waptus River Trail #1310 and Polallie Ridge Trail #1309 head into the Alpine Lakes Wilderness from the same trailhead. The old Salmon La Sac Guard Station, a Forest Service log building dating to the 1930s, still stands near the river. In winter the road is plowed only as far as the Salmon La Sac Sno-Park.

One current note. The 2026 Three Queens Fire area closure on the Cle Elum Ranger District includes Salmon La Sac Campground and runs through October 31, 2026, so check the Okanogan-Wenatchee alerts page before driving up.