The Bay checkerspot (Euphydryas editha bayensis) is a butterfly endemic to the San Francisco Bay region of the U.S. state of California. It is a federally threatened species, as a subspecies of Euphydryas editha. Recently, two authors have advocated a reclassification for this subspecies of the checkerspot common to western North America, Euphydryas editha. The classification, to Euphydryas editha editha, is for reasons of historical precedence; however, this has not been accepted by the scientific community.