In response to the recent delisting of the bald eagle as an endangered species, the Three Affiliated Tribes of the Fort Berthold Indian Reservation, the University of Arizona, and the National Park Service undertook this collaborative study to identify continuities and discontinuities in eagle knowledge and acquisition and use of eagle parts by members of the Mandan, Hidatsa, and Arikara Nation (MHA), and to document cultural resources associated with eagles in three North Dakota national parks. Interviews with tribal consultants who possess eagle rights were integrated with ethnographic, archaeological, and archival data. This research finds that although there have been major changes in how MHA people acquire eagles for personal and religious use since the early 20`" century, beliefs and practices associated with eagle demonstrate cultural continuity. There remains a strict adherence to protocols regarding the handling of eagles and the possession and transfer of eagle knowledge, and there is a persistent belief in the eagle's ability to animate people, objects, and places. The eagle feather remains an indicator of social status, spiritual power, and identity, and eagle parts continue to be crucial elements in the performance of major religious ceremonies. Several site types associated with eagles and eagle trapping were identified, and all three parks either contain eagle resources, or are associated with parts of the eagle landscape. While trapping pits and trapping lodges are no longer used for taking eagles, they retain significance as sources of supernatural power and spiritual knowledge. These sites are spiritually active, and are important places for conducting fasts, seeking visions, and making religious offerings. Tribal consultants believe that the power imbued in these sites is attributed to their past role in the establishment and perpetuation of relationships between their ancestors and the spiritual world during annual trapping expeditions. Both site types are culturally significant in their familial and clan associations, their reflection of traditional land uses unique to the Missouri River environs, and their role in the transformative religious experiences of ancestors. There is a desire within the tribal community to preserve eagle trapping pit sites and, even more so, trapping lodge sites. In order to maintain the sites' spiritual integrity, consultants prefer that they not be accessible to the general public.