HRA historians have worked with the Navajo Nation for nearly three decades on various aspects of the Nation’s water rights claims in the Little Colorado River (LCR) Basin in Arizona. Our research and analysis has focused primarily on the establishment of and additions to the Navajo Reservation in the late-nineteenth and early-twentieth centuries, the historic presence of Navajo groups in the LCR Basin, the Navajo-Hopi land dispute, and the history of on-reservation water development during the first half of the twentieth century. HRA historians have submitted expert reports and provided deposition testimony in two sub-proceedings of the LCR Adjudication.