Margined Whites can be found west of the Great Plains from British Columbia and Alberta south to central California, southern Arizona, and southern New Mexico. The caterpillars feed on native plants in the mustard family. While the adults particularly like to nectar from the flowers of mustards, they also feed from a variety of flowers (this appears to be a flower from the aster family). Adults are generally found in Montana in June and July in forests, meadows, deciduous woods, and streamside habitats.

Photo by: Kelly Dix near the Selway River in Idaho