In northern New Mexico, the Rio Hondo begins high in the Sangre de Cristo Mountains near Taos Ski Valley and flows for approximately into the Rio Grande. Portions of the Rio Hondo are prized as prime spots for bird-watching and fishing. The river was the subject of a 2005 study by the New Mexico Environment Department Surface Water Quality Bureau into the effects of wastewater from Taos Ski Valley, which is discharged from the Village of Taos Ski Valley Waste Water Treatment Plant.