Callophrys augustinus, the brown elfin, is a species of butterfly of the family Lycaenidae, found from Alaska to northern Mexico.

[3] It is found from Newfoundland north and west through the northern United States and the prairie provinces to Alaska.

[4] The larvae feed on Ericaceae species, including Vaccinium vacillans and Ledum groenlandicum in the east.

They feed on a wide variety of plants in the west, including Arbutus and Cuscuta species.

[5] They feed on flower nectar from various species, including Vaccinium, Sanicula arctopoides, Lindera, Salix, Barbarea and Prunus americana.