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 .
Four continents
With the confirmed discovery that Australia was an island continent, the theme of the "Four Continents" lost much of its drive, long before a sixth continent, Antarctica, was discovered. The iconography survived as the Four Corners of the World, however, generally in self-consciously classicizing contexts: for instance, in New York, in front of the Beaux-Arts Alexander Hamilton U.S. Custom House (1907), four sculptural groups by Daniel Chester French symbolize the "Four Corners of the World."