The Boundary Waters Canoe Area Wilderness (BWCAW or BWCA) is a 1,090,000-acre (4,400 km2) wilderness area within the Superior National Forest in the northeastern part of the US state of Minnesota under the administration of the U.S. Forest Service. A mixture of forests, glacial lakes, and streams, the BWCAW's preservation as a primitive wilderness began in the 1900s and culminated in the Boundary Waters Canoe Area Wilderness Act of 1978. It is a popular destination for canoeing, hiking, and fishing, and is one of the most visited wildernesses in the United States.