The Upper Missouri National Wild and Scenic River [UMNWSR] of the Missouri Breaks in north central Montana, USA, is managed by the U. S. Department of the Interior, Bureau of Land Management, in a multiple resource use context The Lewis and Clark National Historic Trail runs the length of the river, and the Nez Perce National Historic Trail cuts across it near the UMNWSR's eastern end. The UMNWSR's eastern end is within the Charles M. Russell National Wildlife Refuge. The UMNWSR's 149-mile length is bordered by a range of prehistoric and historic archeological, architectural, and engineered sites, and landscapes of cultural importance to both Euroamericans and American Indians, 384 of which are identified in this study and plan. The study and cultural resource management plan (CRMP) reported here identified the known cultural resources within the UMNWSR itself and within its adjacent lands in those portions of the UMNWSR where the formal management area is confined between the Missouri River banks. The broader cultural resource study area was required by the Congressional mandate to consider Federal acquisition of more lands under the UMNWSR rubric if those lands held significant cultural values.