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The piedmont of the Mohave Mountains, Arizona formed under conditions of relative tectonic inactivity and external drainage, with the regional base level controlled by the Colorado River. Well-developed geomorphic surfaces formed on sedimentary deposits that range from middle Miocene to Pleistocene in age, but principally on late Miocene (?)-Pleistocene fanglomerate (QTs1) of local origin. Geomorphic units younger than QTs1 generally consist of an erosional platform that may or may not be covered by contemporaneous gravel deposits (typically 1 to 2 m thick). Contemporaneous deposits are generally much coarser than Miocene(?)-Pleistocene fanglomerates on which most erosional platforms were cut, and are interpreted in part as lag gravels. The surfaces are interpreted as erosional- or pediment-terrace sequences that formed on alluvium (rather than hard bedrock) in periods of temporary base-level stability during progressive dissection of the older (QTs1) fans. In general, soils on older surfaces are better developed than those on younger surfaces, but substantial variation in the soils makes local and regional correlation uncertain. Cumulative clast-size distributions of terrace deposits and of pavements developed on the surfaces reveal no distinctive differences useful for correlation. Although climate changes may have influenced formation of the terraces, evidence for that was not found in the clast size distributions of terrace substrates.