Superior National Forest Land Exchange Act of 2019 This bill directs the Department of Agriculture (USDA), if the PolyMet Mining Corporation, Inc., offers to convey 6,690 acres of non-federal land within the Superior National Forest in St. Louis County and Lake County in Minnesota, to accept the offer and, in exchange, convey 6,650 acres of National Forest System land within the forest to PolyMet. The United States shall reserve the mineral rights on 181 acres of such federal land parcel. PolyMet shall waive any payment otherwise owed to it by the United States to equalize the values of the exchanged lands. Upon conveyance, the non-federal lands shall become part of the forest and be managed in a manner consistent with the land and resource management plan applicable to adjacent federally owned lands in the forest. Upon conveyance, the federal land shall: (1) become private land and be made available for any lawful use in accordance with applicable federal, state, and local laws and regulations that pertain to mining and other uses of land in private ownership; and (2) be withdrawn from appropriation and disposal under public land laws and under laws relating to mineral and geothermal leasing.