Boundary Cone is a geologic promontory in the western foothills of Arizona’s Black Mountains east of the Mohave Valley, near Needles, Bullhead City, Oatman, and the Colorado River. Long a prominent landmark in this desert region, it served as a recognizable point for early travelers. It also has religious and cultural importance for several Indigenous peoples connected to the surrounding landscape. In March 2006, the Bureau of Land Management, with concurrence from the Arizona State Historic Preservation Office, found it eligible for the National Register of Historic Places for its traditional, religious, and cultural significance to several Indigenous tribes. Today it remains both a striking natural feature and a place of enduring meaning.