Pueblo del Arroyo sits at the bend of the Chaco Wash where the canyon widens, a four-storey great house of about 280 rooms. It is one of the later builds — most of the construction is twelfth century — and the masonry shows it: thin, even slabs in the "McElmo" style that mark the final Chacoan phase.
At the back of the pueblo, a circular triple-walled structure is unique in the canyon, its purpose still debated. A short walking trail leads through the rooms; about 30 minutes is enough.