The source of water for large regional springs in southern Nevada has been well documented by numerous investigators. Regional springs in Nevada have been characterized on the basis of geochemical data and discharge characteristics. For example, spring discharge at the Ash Meadows National Wildlife Refuge west of Las Vegas, and the Moapa Valley National Wildlife Refuge northeast of Las Vegas, is dependent on groundwater discharge from the regional carbonate-rock aquifer of the Basin and Range physiographic province. However, the source of water for springs in the Lake Mead National Recreation Area is not as well documented because of complex local geology and limited hydrogeologic information. In this study, analysis of discharge data collected at Rogers Spring, the largest spring in the Lake Mead National Recreation Area, and precipitation data from a nearby weather station, suggest that the spring’s source may be a mixture of recharge occurring within the drainage area, and recharge from areas outside the hydrographic basin. Temperature, isotopic and geochemical data provide further evidence for a regional source of discharge at Rogers Spring.