The Stillaguamish Watershed (HUC 17110008) covers an area of approximately 680 square miles in western Washington State. It is fed by several tributaries, including the North Fork, South Fork, and Pilchuck Creek. The watershed is characterized by a high snowpack in the winter, which contributes to the abundant surface water in the spring and summer months. Reservoirs within the watershed collect water for drinking and agricultural use, and contain constituents such as sediment and nutrients that can impact water quality. The area is also known for its heavy rainfall and mild temperatures, with an average annual precipitation of 50 inches. In recent years, the watershed has been affected by climate change, with warmer temperatures contributing to reduced snowpack and altered hydrology. The Stillaguamish Watershed is home to a diverse array of plant and animal species, including several threatened and endangered species.