Pliocene to Recent lacustrine and playa deposits in the southwestern UnitedStates preserve a sedimentary record of climate change and tectonic activity. The middle Pliocene record is particularly important, because it represents the beginning of the glacial-interglacial climate that characterizes the Quaternary. However, continental sedimentary records of this time period are scarce. Well-exposed playa margin deposits in the Confidence Hills, southern Death Valley National Monument, California, were deposited between about 2.5 and 1.5 Ma. Detailed chronometric control is provided by tephrochronology and magnetostratigraphy.A new stratigraphic unit, the Confidence Hills Formation, is herein defined. This formation consists of interbedded fine-to coarse-grained siliciclastic strata with abundant gypsum and anhydrite. Ten distinct sedimentary lithofacies were defined within the Confidence Hills Formation based on variations in their siliciclastic and evaporite components. Lithofacies dominated by siliciclastic components include the siltstone, fine-grained sandstone, coarse-grained sandstone, and interbedded coarse-grained sandstone/conglomerate lithofacies. Those dominated by evaporitic components include the halitic mudstone/siltstone/fine-grained sandstone, gypsiferous mudstone/siltstone/fine-grained sandstone, banded anhydrite, and thin-bedded to massive anhydrite lithofacies. The siliciclastic component shows an overall coarsening-and thickening-upward trend, from dominantly thinly bedded siltstone in the lower part of the section to dominantly medium-bedded, fine-to medium-grained sandstone in the upper part. Superimposed on this pattern is variation in amounts, types, and textures of evaporite deposits.The lithofacies observed in the Confidence Hills are readily interpretable using the classification of saline lake subenvironments developed by Hardie et al. (1978). The halitic mudstone lithofacies is interpreted as having been deposited within the center of the saline lake. The anhydrite-and gypsum-bearing lithofacies are interpreted as having been deposited in the saline mudflat subenvironment marginal to the saline lake. The siliciclastic sediment was derived primarily from the Owlshead Mountains to the west and deposited by streamflood mechanisms in a distal alluvial fan setting.The overall coarsening-upward sequence is interpreted as recording progradation of one or more marginal alluvial fans into a saline lake. The depositional rate was fairly constant at about 29 mm/ka. Major changes in depositional setting occurred