Within Four Corners of the United States, which unit of the National Park Service has ruins of the indigenous tribes and is within the boundaries of the Navajo Nation?
Four Corners:  In addition to the monument, commonly visited areas within Four Corners include Monument Valley, Mesa Verde National Park, Chaco Canyon, and Canyon de Chelly National Monument. Canyon de Chelly National Monument: Canyon de Chelly National Monument ( ) was established on April 1, 1931 as a unit of the National Park Service. Canyon de Chelly National Monument:  Located in northeastern Arizona, it is within the boundaries of the Navajo Nation and lies in the Four Corners region.
i don't know