Some rooms in Square Tower House were devoted to secular, others to ceremonial purposes. The former have angular corners; the latter are circular. The rectangular rooms were constructed above ground; the circular were subterranean. These rooms do not differ radically from those of Spruce Tree House and other cliff dwellings. They have similar windows, door openings, and supports of balconies. There is little difference in the size of the stones used in the masonry at different heights. The absence of a cave recess in the rear of the building is significant, as it allowed the cliff to be used as the back wall of the rooms.
Square Tower House measures about 138 feet from its eastern to its western end. There are no streets or passageways as at Spruce Tree House and Cliff Palace, and no open spaces except on the kiva roofs. The rooms are continuous and compactly constructed. Excepting the spaces above the kivas, the walls are united from one end of the cave to the other. The foundations of the secular rooms are constructed on two levels, an upper and a lower. These rooms occupy the intervals between the kivas, never in front of them.
The tower is, of course, the most conspicuous as well as the most interesting architectural feature of the ruin, being visible for a long distance as one approaches Square Tower House. Its foundation rests on a large boulder situated in the eastern section of the cave floor. This tower has three walls constructed of masonry, the fourth being the perpendicular rear wall of the cave. The masonry of the tower stands about 35 feet above the foundation, but the foundation boulder on which it stands increases its height over 5 feet.
On a projecting rock on the west side above the tower is the wall of a small, inaccessible room which may have been used as a lookout or as an eagle house.
The lowest story of the tower is entered from plaza B, and on the east side there are three openings, situated one over another, indicating the first, second, and third stories, but on the south side of the tower there are only two doorways. The roof of the lowest room is practically intact, showing good workmanship, but about half of its floor is destroyed. The upper walls of the second-story room have the original plaster, reddish dado below and white above. Although the third and fourth stories are destitute of floors, they are plastered.