Four Corners
Six governments have jurisdictional boundaries at the Four Corners Monument: the states of Arizona, Colorado, New Mexico, and Utah, as well as the tribal governments of the Navajo Nation and Ute Mountain Ute Tribe. The Four Corners Monument itself is administered by the Navajo Nation Department of Parks and Recreation. Other tribal nations within the Four Corners region include the Hopi and other Ute. The Four Corners is home to the capital of the Navajo tribal government at Window Rock, Arizona. The Ute Mountain Ute Tribal headquarters are located at Towaoc, Colorado.
Quadripoint
The earliest known quadripoint involving modern nation states existed from 1817 to 1821 where the present Alabama–Mississippi state line crossed the 31st parallel border between Spain and the United States. During that period, the part of West Florida between the Pearl and Perdido rivers (which Spain still owned but the United States forcibly occupied and annexed in 1810 after belatedly claiming it as part of the Louisiana Territory purchased from France in 1803) was subdivided and allocated partly to the State of Mississippi and partly to the Territory (and later State) of Alabama. There resulted, at the intersection of demarcated boundaries, an international quadripoint of four territories, which in the United States were named (clockwise) Baldwin and Mobile counties of Alabama and Jackson and Greene counties of Mississippi, though Mobile and Jackson Counties were actually still Spanish.