The Anasazi were an ancient Native American culture that lived in the Four Corners region of the United States, primarily in what is now Arizona, New Mexico, Colorado, and Utah. They are also known as the Ancient Pueblo Dwellers, and were active from around 200 to 1300 CE. They built large stone structures, including cliff dwellings, and developed a complex agricultural system. They are believed to have been the ancestors of modern Pueblo peoples.