Bears Ears National Monument Expansion Act This bill expands the boundaries of the Bear Ears National Monument in Utah. The Department of the Interior and the Department of Agriculture USDA shall administer the lands under their jurisdictions within the expanded boundaries: (1) as part of the monument; and (2) in accordance with Presidential Proclamation 9558, dated December 28, 2016, which provided for establishment of the monument. Interior and USDA shall promptly carry out the proclamation's provisions, including the provisions requiring them to engage the Bear Ears Commission to: ensure the proper care and management of the objects identified; ensure that management decisions affecting the monument reflect tribal expertise and traditional and historical knowledge; and provide guidance and recommendations on the development and implementation of management plans and on management of the monument. The National Park Service shall administer Natural Bridges National Monument and those portions of Glen Canyon National Recreation Area that are within the expanded boundaries as part of the monument. Interior and USDA may acquire lands, waters, or interests in land that are located within the revised boundaries of the monument by donation, purchase, or exchange.