Eurymus occidentalis Dyar, 1903 Colias occidentalis, the western sulphur or golden sulphur, is a butterfly in the family Pieridae found in North America.

Its range includes the Pacific Northwest and parts of British Columbia.

[1] The flight period is from late May until early July.

[1] Its habitats include ocean bluffs, forest openings, mountain slopes, and subalpine meadows.

[1] Its larvae feed on flowers like the Vicia spp., Lupinus spp., Lathyrus spp., and Thermopsis spp.