The Phytomyza ilicis species group is the only taxon in the phytophagous family Agromyzidae (Diptera: Schizophora) known to feed on hollies (Aquifoliaceae: Ilex L.) in North America, mining within the living leaves as larvae. The clade is represented here by 11 species native to eastern North America, although P. vomitoriae has been introduced into California. The sole European holly leafminer, Phytomyza ilicis Curtis, is also present in western North America following introduction. The North American fauna is revised, following a molecular treatment of the group by Scheffer and Wiegmann (Mol. Phylog. Evol. 17: 244–255; 2000), who discovered several previously undescribed species. These new species, Phytomyza ambigua spec, nov., Phytomyza leslieae spec, nov., Phytomyza lineata spec. nov., and Phytomyza wiggii spec, nov., are formally named, and all adults and puparia of North American species are described, illustrated, and included in an updated identification key. A lectotype is designated for P. ilicis.