Plants densely cespitose. Culms 10-30 cm, distally finely scabrous. Leaves 2.5-5 mm wide. Inflorescences: proximal bracts shorter than or exceeding inflorescences; spikes contiguous, overlapping, erect, distinct, short-pendunculate, short-oblong or elongate, 8-20 × 4-7 mm; lateral 1-3 spikes pistillate pedunculate, of similar length; terminal spike gynecandrous. Pistillate scales light to dark brown with hyaline margins, broadly lanceolate or ovate, equaling perigynia, midvein same color as body, inconspicuous, raised, prominent, short-mucronate. Perigynia ascending, chestnut, veinless, ovate, 3-3.5 × 2-2.5 mm, apex abruptly beaked, papillose; beak 0.3-0.4 mm, entire or shallowly bidentate, smooth. Achenes nearly filling body of perigynia. 2n = 52, 54.
Specimens from California determined as Carex albonigra are provisionally assigned here; these need further study because they differ from the typical Rocky Mountain forms.