 Chaco scholars estimate that it required more than 500,000 man-hours, 26,000 trees, and 50 million sandstone blocks to erect Chetro Ketl.The great house is a D-shaped structure; its east wall is 280 feet (85 m) long, and the north wall is more than 450 feet (140 m); the perimeter is , and the diameter of the great kiva is .Chetro Ketl contained approximately 400 rooms and was the largest great house by area in Chaco Canyon, covering nearly .