Estimates of the number of individuals whose remains had not yet been repatriated as of the early 2020s ranged into the hundreds of thousands — a figure that is itself uncertain because the inventory process has not been completed at all institutions.

The federal government’s own agencies — including the Army Corps of Engineers, the National Park Service, and other bodies that hold or manage collections of Native American human remains — have been among the less responsive institutions under the law, a pattern that has drawn criticism from tribal nations and from advocacy organizations working on repatriation issues.

The Biden administration issued regulations in 2023 attempting to strengthen NAGPRA’s implementation, addressing some of the specific ways in which institutions had used ambiguities in the law to delay or avoid repatriation.

Those regulatory changes reflected more than three decades of experience with the law’s implementation and the specific points at which the framework had proven insufficient.