Four Corners is the only place in the United States where four states meet. This famous point is located on the Navajo reservation. Who are Arizona’s neighbors? Arizona’s boundaries touch five states and one country. A boundary is a dividing line between two places. To the west are California and Nevada. The Colorado River flows between these two states and Arizona, forming a natural boundary. A natural boundary follows something that already exists, like a river. Man has made Arizona’s other three boundaries. North of Arizona is the state of Utah. East is the state of New Mexico. At the northeastern tip of Arizona is a place called Four Corners, the only place in the country where four states meet. These states are Arizona, New Mexico, Utah, and Colorado. Colorado is not a boundary of Arizona, but New Mexico and Utah are. Look at a map of the United States and picture how you can be in four states at the same time. The country of Mexico is south of Arizona. The dividing line between Arizona and Mexico is called an international boundary because it divides the countries from each other. Chapter 2 • The Land  21