Celastrina lucia, the lucia azure, northern azure, eastern spring azure or northern spring azure, is a species of butterfly of the family Lycaenidae.

It is found eastern North America, ranging from the Maritimes south through the Appalachian Mountains to West Virginia.

[3] The larvae feed on Vaccinium species, including V. pallidum.

Until the early 1990s, most North American azures were thought to be a single species, Celastrina ladon.

More recently, research has revealed that there are many different species of azures, including C. lucia,[4] which had been treated as a subspecies of C. ladon.