The taxonomy of the East Pacific land crab Johngarthia planata (Stimpson, 1860) is reviewed and a neotype designated to stabilize the taxonomy of this species. The population of J. planata is found to be restricted to inshore islands and the continental mainland coast of the tropical and subtropical Pacific coast of America. A new species, Johngarthia oceanica sp. nov., is described for populations that occur on the oceanic Clipperton and Socorro islands. Johngarthia oceanica sp. nov., can be separated from J. planata by the broad, subrectangular mesial lobe of the infraorbital margin (narrow, subtriangular in J. planata) and a dorsal carapace that is dark yellow to brightly orange with or without black areas of different extension (homogeneously red to maroon in J. planata). The distribution of J. planata is modeled using MaxEnt and the biogeography of East Pacific species of Johngarthia is discussed. The conservation status of the Clipperton population of J. oceanica sp. nov. deserves special attention because this population may be threatened by introduced rats.