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 .
List of landlocked U.S. states
A landlocked state in the United States is any state whose territorial boundaries do not touch an ocean, gulf, or bay. All of the landlocked states in the U.S. are situated in the contiguous 48 states on the North American mainland.The 16 singly landlocked states, and the District of Columbia, with routes to their nearest ocean, gulf, or bay:The 10 doubly landlocked states, with routes to their nearest ocean, gulf, or bay:Nebraska is the only triply landlocked state. To reach an ocean, gulf, or bay from Nebraska, one must travel through at least three states, such as through Missouri, Tennessee, and North Carolina to reach the Atlantic Ocean, or through Wyoming, Idaho, and Oregon to reach the Pacific.