The St. Croix River near Prescott is the final stretch of the river before it enters into the Mississippi River. It is located downstream of where Valley Creek, the Willow River (WI), and the Kinnickinnic River (WI) enter into the St. Croix River. This entire section of the river is part of Lake St. Croix. The river passes several parks, including Afton State Park, Kinnickinnic State Park, and St. Croix Bluffs Regional Park.The St. Croix River at Prescott, River Mile 0.3 is one of the main monitoring stations of the Council's Large Rivers Conventional Monitoring Project. It measures the water quality of the St. Croix River just before it flows into the Mississippi River. This site sometimes experiences tailwater backflow from the Mississippi River. USGS station 05344500 is located near this water quality monitoring station and measures hydrological data of the river.The St. Croix River is a 164 mile tributary of the Mississippi River which begins in Douglas County of northwestern Wisconsin. It flows into the Mississippi River near the city of Prescott, WI. The watershed of the river covers approximately 7,760 square miles, split between Minnesota and Wisconsin. It is mostly covered with forests and wetlands, although there is still a sizable amount of agriculture in the south. Development also continues to grow in the St. Croix River watershed. The St. Croix River is designated as a National Scenic Riverway by the federal National Wild and Scenic Rivers Program.