Casa Grande appears to be the sole surviving remnant of an extensive and
important class of remains in the southwest. These remains occur usually
in large groups or clusters, and Casa Grande is no exception. The name
has been ordinarily applied to a single house structure standing near
the southwestern corner of a large area covered by mounds and other
debris; but some writers have applied the term to the southwestern
portion of the area, others to the whole area.

Probably no two investigators would assign exactly the same limits to
this area, as its margins merge imperceptibly into the surrounding
country. The accompanying map (plate CXII) shows the limits of the ruins
as interpreted by the writer. The surface covered by well-defined
remains, as there shown, extends about 1,800 feet north and south and
1,500 feet east and west, or a total area of about 65 acres.

Casa Grande ruin occupies a position near the southwestern corner of the
group, and its size is insignificant as compared with the entire cluster
of ruins, or even with the remains of the large structure which occupied
the north-central part of the area. The contour interval on the map is 1
foot, sufficiently small to show much surface detail. The depressions
are indicated by dotted contours.

Within the area shown on the map there are a large number of mounds,
more or less leveled by long-continued exposure to the elements. Some
appear to be quite old, others represent buildings which were standing
within the historic period, and many interesting features are presented
which can not even be alluded to here.

Casa Grande proper was one of the smallest of the house clusters, but it