Euphylax feldmanni new species from the late Eocene Hoko River Formation, northwestern Olympic Peninsula, Washington, represents the first occurrence of Euphylax in pre-Oligocene strata, the earliest fossil record for the subfamily Podophthalminae, and the first record of the genus from the eastern North Pacific. This small, aberrant crab is one of 26 described species of decapod crustaceans from an unusual allochthonous invertebrate assemblage of the upper Eocene Hoko River Formation conglomerates at Kydikabbit Point, on the Makah Indian Nation, northwestern Olympic Peninsula, Washington, U.S.A. Species of Euphylax live today in the Pacific Ocean from Baja California south to Peru and Chile, and have been found as fossils from the Pleistocene of Jamaica, the Miocene of Costa Rica, Brazil, and Haiti, and questionably from Malaysia and Japan. The discovery of a fossil species of Euphylax from the Pacific Northwest, U.S.A. greatly expands the paleobiogeography of the genus.