The number of wildland fires and burned areas in the U.S. is on the rise as a result of a warming climate, drought, and increasing human ignitions. Wildland fires alter the watershed hydrologic cycle by modifying soil and forest cover properties, but the effects vary widely across the continental U.S. due to differences in fire severity and burned area, background climate, and watershed conditions. Climate variability such as drought may mask the effects of wildland fire on water supplies. Although forests and rangelands provide more than half of U.S. water supplies, the long-term impacts of wildland and prescribe fire on water supplies have not been measured previously nor factored into water management strategies. Researchers at the Forest Service’s Eastern Forest Environmental Threat Assessment Center developed a practical framework to evaluate fire impacts on water resources by synthesizing 30-year-old records of wildland fire, climate, and river flow for 162 locations across the U.S. They discovered that wildland fires enhanced annual river flow in western regions with a warm temperate or humid continental climate (the semi-arid Lower Colorado River in particular). In contrast, repeated prescribed burns did not significantly alter river flow in the subtropical Southeast. These outcomes offer new insights into the potential role of wildfire and prescribed fire in water supply augmentation, flood control, and landslide hazard mitigation under a changing climate. These findings can help land managers consider local watershed conditions and design effective forest management practices, including prescribed burning, that reduce fire risk and strengthen forest resilience to drought and diseases.