Echinargus isola, or Reakirt's blue, is a butterfly of the family Lycaenidae.

Adults are on wing from June to October in the north and year round in south.

[1] Its habitats include fields, gardens, open areas, and host plants.

[2] The larvae feed on Fabaceae, particularly mesquites (Prosopis species).

[1] Adults feed on flower nectar from spearmint, white sweet clover, and a variety of other herbs.