This study reports on the pseudoscorpion fauna of the subterranean ecosystems of northern Arizona, U.S.A. Our work resulted in the descriptions of two new species, Hesperochernes bradybaughi sp. nov. and Tuberochernes cohni sp. nov. (Chernetidae) and the range expansion of one species, Larca cavicola (Muchmore 1981) (Larcidae). All of these species were cave-adapted and found within caves on Grand Canyon-Parashant National Monument in northwestern Arizona. Based upon this work, the genus Archeolarca Hoff and Clawson is newly synonymized with Larca Chamberlin, and the following species are transferred from Archeolarca to Larca, forming the new combinations L. aalbui (Muchmore 1984), L. cavicola (Muchmore 1981), L. guadalupensis (Muchmore 1981) and L. welbourni (Muchmore 1981). Despite intensive sampling on the monument, the two new species were detected in only one cave. This cave supports the greatest diversity of troglomorphic arthropod species on the monument—all of which are short-range endemics occurring in only one cave. Maintaining the management recommendations provided by Peck and Wynne (2013) for this cave should aid in the long-term persistence of these new pseudoscorpion species, as well as the other troglomorphic arthropods.