Only once in USA geography:
The traveler must arrive on the New Mexico side, since there is only one road in miles. The Navajos operate retail similar to a swap-meet at the monument where the creation of four corners of states comes together. Visitors can be in four states at the same time with hands and feet. A couple of years ago, big news was that the GPS true readings showed the correct location is southeast about 1/3 mile, located toward the westbound San Juan river. Rangeland for grazing in all directions, no one seems to care. Notice the Sleeping Ute mountain to the northeast in Colorado. It has east toe, west toe, knees, and impressive (rounded) Ute Peak at 9978 feet.
United States highway 160 heads east and west from Arizona into the tiny corner of New Mexico, and on into Colorado. On the New Mexico piece, a local road goes to the attraction.