Four Corners, Arizona, Colorado, New Mexico, and Utah

The four corners refers to the spot in the southwestern U.S. where the corners of four states meet. It includes the northwestern corner of New Mexico, the northeastern corner of Arizona, the southwestern corner of Colorado, and the southeastern corner of Utah. The borders for these four states are also unusual because they run along straight lines and do not follow longitudinal lines, latitudinal lines, or natural boundaries. The Navajo reservation is centered almost exactly on the four corner boundaries and extends into three of the four corner states.