Plants densely cespitose. Culms (5-)15-45 cm. Leaves: sheaths adaxially white-hyaline, summits U-shaped or rounded, often prolonged to 2.5(-3) mm beyond collar; distal ligules 1.5-2.5(-3) mm; blades 3-5 per fertile culm, often channeled, occasionally folded, becoming trigonous toward tip, 5-20 cm × 1-2.5(-3) mm, if not folded, margins revolute. Inflorescences usually dense, stiff, gold to brown or brown and green, 1.5-3.5(-4) cm × 10-15 mm; proximal internode 4-10 mm; 2d internode 2-5 mm; proximal bracts scalelike to bristlelike, shorter than inflorescences. Spikes (3-)4-7, distant, distinct, ovoid to broadly ovoid, 12-15 × 5.5-8 mm, base rounded to attenuate, apex acute to truncate. Pistillate scales gold or brown, usually with pale to green midstripe, lanceolate to ovate, 3.7-5.1 mm, usually ± equaling and covering perigynia, margin white-hyaline, 0.1-0.3 mm wide, apex acute to acuminate. Anthers early deciduous or short-persistent. Perigynia ascending, greenish or pale gold to brown, conspicuously (0-)4-9-veined abaxially, conspicuously 0(-4)-veined adaxially, narrowly ovate to broadly ovate, flat or plano-convex, 3.8-5.2 × 1.5-2.3 mm, 0.4-0.5 mm thick, margin flat, including wing 0.3-0.5 mm wide, ciliate-serulate at least on distal body, not crinkled, without glossy metallic sheen; beak brown to red-brown or gold with white-hyaline tip, cylindric, unwinged, ± entire for 0.6 mm, abaxial suture with conspicuous white margin, distance from beak tip to achene 1.8-2.2 mm. Achenes ovate to broadly ovate or, occasionally, elliptic, 1.5-2 × 0.8-1.1(-1.2) mm, 0.3-0.5 mm thick. 2n = 84.

Fruiting summer. High-montane to alpine areas, usually rocky soils; 1200-4000 m; Alta., B.C.; Alaska, Calif., Colo., Idaho, Mont., Nev., Oreg., Utah, Wash., Wyo.

Reports of Carex phaeocephala from northern Canada are based on other species, mostly C. tahoensis.