Plants without conspicuous rhizomes. Culms 15-80 cm, 1.5-2 mm wide basally, 0.5 mm wide distally. Leaves: sheaths tight, green, fronts white-hyaline; ligules less than 2 mm, wider than long; widest leaf blades 1.5-2.5 mm wide. Inflorescences with 5-10 spikes, 2-5 cm × 5-10 mm; proximal internodes 1-2 times as long as proximal spikes; proximal bracts 1-2 cm; spikes with 5-10 erect perigynia. Pistillate scales brown with green midvein, ovate, 2.7-3.6 × 1.4-2.1 mm, body longer and wider than perigynium, apex awned. Anthers not measured. Perigynia pale green to pale brown, veinless or obscurely veined abaxially, 2.6-3.5 × 1.2-1.5 mm, margins serrulate distally; beak 0.8-1.5 mm, apical teeth 0.3-0.5 mm. Achenes elliptic-circular, 1.5-1.7 × 1.1-1.2 mm.

Fruiting late spring-early summer. Swamps, mesic to wet-mesic grasslands and open forests; 300-500 m; Alta., Man., Ont., Sask.; N.Dak., S.Dak.

Carex hookerana was collected once in Ontario along Lake Superior´s north shore, but its status in Ontario is unclear.