Four Corners is the only place in the U.S. where the boundaries of four states join. The states are: Utah, Colorado, New Mexico and Arizona.
The spot is in an out of the way place that the tourist must make an effort to arrive at. The actual bisection point is indicated by a granite slab showing the state boundaries. Once you have seen it, you probably will never need to return.
The site is on an Indian reservation and is run by the tribe. You pay $3.00 to get in. Many small merchants are all around the site ready to sell you souviners, food and drink. I spent maybe five minutes total at the place.