Washington State Fish & Wildlife has established 8 campgrounds along Tucannon Rd, free with Discover Pass, 21 day stay limit. This review and photos are for campsite #8.
There is a pit toilet, and individual sites with a picnic table and fire pit, but nothing else. The sites are sort of close together, no division between them, and would be awkward if they were completely full. The campgrounds get progressively less crowded the further up the road you go, so by campground #8 it was completely empty where campgrounds 1 through 4 were pretty packed.
Zero cell reception here in this entire area. This is a popular area for hunters, so during hunting season heads up for that.