Southern Utah comprises 4 major physiographic divisions: the Great Basin, Colorado Plateau, Central Rocky Mountains, and Southern Rocky Mountains, which have been partitioned into faunal regions. We discuss the uniqueness of southern Utah and the amount of land set aside for recreation and preservation, and we encourage the study and preservation of its water resources. The stonefly (Plecoptera) fauna of 13 counties in southern Utah was surveyed. We found 58 species representing 34 genera and 8 families. Three new state records for Utah and many new county records for southern Utah are presented, along with a discussion of distribution patterns and faunal affinities of each species. Distribution patterns indicate a historical connection between the Sevier River and the Colorado drainage and a separation of faunal areas within the Central Rocky Mountains at boundaries between the Wasatch Mountains, Wasatch Plateau, and the Southern High Plateau. The uniqueness of the isolated Abajo and LaSal Mountains, the Virgin River valley, and other faunal areas in southern Utah is presented.