The term 'Monument Valley Formation' refers to a mesa, which is an elevated area of land with a flat top and steep sides. It is located in the Four Corners region of the United States, where Arizona, New Mexico, Colorado, and Utah meet. The formation is composed of sedimentary rocks that were deposited over millions of years and are now exposed due to erosion. Monument Valley is a popular tourist destination, known for its iconic sandstone buttes and mesas.