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?
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. Canyon de Chelly National Monument:  Reflecting one of the longest continuously inhabited landscapes of North America, it preserves ruins of the indigenous tribes that lived in the area, from the Ancestral Puebloans (formerly known as Anasazi) to the Navajo.
i don't know