Sears-Kay Ruin is a Hohokam archaeological site in the Tonto National Forest near Carefree, Arizona, preserving a desert foothill fortification built around 1050 AD and abandoned around 1200 AD. One of many Hohokam forts in a region where they also built villages, it reflects a long occupation of these foothills. The ruin originally contained 40 rooms and may have housed about 100 people; its unusual rounded-corner Mystery Room may belong to an earlier building phase. Rediscovered in 1867, the site later took its name from the Sears-Kay Ranch established in 1887 and was listed on the National Register of Historic Places in 1995.