The Rainy River-Headwaters Watershed (09030001) lies in northeastern Minnesota and covers approximately 2,954 mi2 or 1,890,689 acres. A total of 1,273 lakes (>10 acres) and 408 stream reaches reside within this watershed. Streams are generally small to moderate in channel size, short, and vary in gradient; many are direct tributaries to the many lakes in the watershed. Both drinking water quality and the recreational value of lakes and streams are important to the health and wealth of local economies throughout this watershed. The waterbodies also provide habitat for aquatic life, riparian corridors for wildlife. The immaculate waters found within this watershed not only produce some of the highest quality fisheries in the state but also offer visitors many scenic and natural views. The most visited wilderness area (Boundary Waters Canoe Area) in the United States is located within this watershed, with water as a major focal point. Today over 99% of the Rainy River-Headwaters Watershed is undeveloped and utilized for timber production, hunting, fishing, hiking, and other recreational opportunities. Large tracts of public land exist within this watershed, including county land, national and state forests, wildlife management areas, scientific and natural areas, state parks, and a national park. In 2014, the Minnesota Pollution Control Agency (MPCA) undertook an intensive watershed monitoring (IWM) effort of surface waters within the Rainy River-Headwaters Watershed. Sixty-two stream stations were sampled for biology at the outlets of variable sized subwatersheds. These locations included the mouth of the Ash, Bear Island, Black Duck, Cross, Dumbbell, Dunka, Island, Little Indian Sioux, Little Isabella, Shagawa, South Kawishiwi, and Stony rivers, as well as the upstream outlets of major tributaries, and the headwater outlets of smaller streams. Cook and Lake County Soil and Water Conservation Districts (SWCD) and Vermilion Community College completed stream water chemistry sampling at the outlets of 13 streams. In addition, the MPCA, Lake County SWCD, Natural Resources Research Institute, National Park Service, and local volunteers completed lake monitoring on 60 lakes. In 2016, a holistic approach was taken to assess all surface waterbodies within the Rainy River-Headwaters Watershed for support of aquatic life, recreation, and consumption (where sufficient data was available). Additional data from other state and federal agencies, local units of government, lake associations, and/or individuals were used in the assessment of these designated beneficial uses. Sixty-four stream segments and 245 lakes were assessed in this effort.