Quadripoint
The Four Corners Monument is the only point in the United States where four states meet: Colorado, Utah, New Mexico, and Arizona meet at right angles. The United States first acquired the area now called Four Corners from Mexico after the Mexican–American War in 1848. In 1863 Congress created Arizona Territory from the western part of New Mexico Territory. The boundary was defined as a line running due south from the southwest corner of Colorado Territory, which had been created in 1861. By defining one boundary as starting at the corner of another Congress ensured the eventual creation of four states meeting at a point, regardless of the inevitable errors of boundary surveying. The monument is centered at .
U.S. Route 491
U.S. Route 491 (US 491) is a north–south U.S. Highway serving the Four Corners region of the United States. One of the newest designations in the U.S. Highway System, it was created in 2003 as a renumbering of U.S. Route 666 (US 666). With the 666 designation, this road was nicknamed the "Devil's Highway" because of the significance of number 666 to many Christian denominations, which is believed by some that 666 is the Number of the Beast. This Satanic connotation, combined with a high fatality rate along the New Mexico portion, convinced some people the highway was cursed. The problem was compounded by persistent sign theft. These factors led to two efforts to renumber the highway, first by officials in Arizona, later in New Mexico. There have been safety improvement projects in recent years, and fatality rates have subsequently decreased.