The U.S. Geological Survey (USGS) has collected hydrologic information in New Mexico since 1889, beginning with the first USGS streamflow-gaging station in the Nation, located on the Rio Grande near Embudo, New Mexico. Water-resources information provided by the USGS is used by many government agencies for issuing flood warnings to protect lives and reduce property damage,managing water rights and interstate water use, protecting water quality and regulating pollution discharges, designing highways and bridges, planning, designing, and operating reservoirs and watersupply facilities, monitoring the availability of groundwater resources and forecasting aquifer response to human and environmental stressors, and prioritizing areas where emergency erosion mitigation or other protective measures may be necessary after a wildfire. For more than 100 years, the Cooperative Water Program has been a highly successful cost-sharing partnership between the USGS and water-resources agencies at the State, local, and tribal levels. It would be difficult to effectively accomplish the mission of the USGS without the contributions of the Cooperative Water Program.