Ground-water discharge deposits, also called “spring” or “wetland” deposits, form in arid environments as water tables rise and breach the ground surface during periods of enhanced effective precipitation. Where preserved, these deposits contain information on the timing and elevation of past ground-water highstands. This information, in turn, can be used to evaluate conceptual and/or numerical models of past climate conditions. Spring deposits have been identified in all of the major deserts of North America, but they have been studied in detail at only a handful of localities. We used radiocarbon dating of small land snails to establish the chronology of spring deposits at two locations: (1) the San Pedro Valley of southern Arizona, located at the boundary of the Sonoran and Chihuahuan Deserts, and (2) Valley Wells, located in the eastern Mojave Desert. Multiple lines of evidence suggest that hydrologic conditions at both locations remained relatively constant during full glacial times before falling at the end of the late glacial period, rebounding briefly during the Younger Dryas cold event, and falling again at the onset of the Holocene. In southern Arizona, the timing of these changes coincides with large variations in the oxygen isotopic composition of calcite from a nearby speleothem to the west and changes in lake levels at Pluvial Lake Cochise to the east. Thus, our studies not only provide records of past hydrologic conditions in the American Southwest, but also further validate the concept of ground-water discharge deposits as recorders of past climate change.