Perennials, 1.5-5(-7) cm (forming densely compact cushions); taprooted, caudex branches rhizomelike, relatively numerous, short, and slender. Stems erect (simple, scapiform), sparsely to densely hirsuto-villous, minutely glandular. Leaves basal (persistent; petioles linear, 0.5-1 mm wide); blades obovate-spatulate, 3-16 × 3-6 mm (bases abruptly expanded), margins mostly 3-lobed, rarely entire or 2-lobed (lobes 2-8 mm, oblong to ovate or obovate, rounded), ultimately entire, coarsely ciliate, faces sparsely to densely hirsute, ± minutely glandular. Heads 1. Involucres 5-7 × 8-11 mm. Phyllaries in 2-3 series (commonly purplish, sometimes at tips only), sparsely to densely hirsuto-villous to villous (hairs usually with colored cross walls), minutely glandular. Ray florets 15-32; corollas white to bluish, 6-10 mm, laminae not coiling or reflexing (spreading). Disc corollas 3.2-4.5 mm. Cypselae 2-2.6 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae, inner of 15-21 bristles. 2n = 18.

Flowering Jul-Sep. Cliffs and gravelly slopes, ridges, ledges; of conservation concern; 1500-2150 m; B.C.; Wash.

The compactly cespitose, cushionlike habit of Erigeron salishii may obscure the slender, loose branches of the caudex in herbarium specimens. The species otherwise is similar to E. vagus; the leaves of E. salishii are mostly smaller and the hairs thinner and looser (villous) compared to those of E. vagus.