Satyrium acadica, the Acadian hairstreak, is a butterfly of the family Lycaenidae. It is found in North America from British Columbia east to Nova Scotia and south to Idaho, Colorado, the northern Midwest, Maryland, and New Jersey. The wingspan is 29–38 mm. There is one tail on each hindwing. The upperside is brown grey, while the underside of the hindwings is grey. Adults are on wing from June to August in one generation per year. They feed on flower nectar of various flowers such as butterflyweed, milkweeds, and thistles. The larvae feed on the leaves of Salix species, including S. nigra and S. sericea. The species overwinters as an egg.