North Cascades National Park is an American national park in the state of Washington. At more than , it is the largest of the three National Park Service units that comprise the North Cascades National Park Complex. North Cascades National Park consists of a northern and southern section, bisected by the Skagit River that flows through Ross Lake National Recreation Area. Lake Chelan National Recreation Area lies on the southern border of the south unit of the park. In addition to the two national recreation areas, other protected lands including several national forests and wilderness areas, as well as Canadian provincial parks in British Columbia, nearly surround the park. North Cascades National Park features the rugged mountain peaks of the North Cascades Range, the most expansive glacial system in the contiguous United States, the headwaters of numerous waterways, and vast forests with the highest degree of flora biodiversity of any American national park.