The Native American Graves Protection and Repatriation Act (NAGPRA) claims process can be frustrating for Native American communities due to hindrances such as the lack of provenience and provenance of collections. Through historic research on and preliminary analysis of Santa Catalina Island archaeological collections assembled by Ralph Glidden and held by museums across the United States, the authors have discovered that much of the documented provenience and provenance information is missing, wrong, or at best more complicated than previously thought. The authors assert that background research of collections is imperative to ensure that ancestral remains are returned to the appropriate lineal descendants or Native American descendant community. Further, the Glidden collections show that disputed provenience and provenance information has massive implications for NAGPRA claims made by non‐federally recognized tribes, such as the Gabrielino/Tongva, the Indigenous inhabitants of Santa Catalina and the Los Angeles Basin.