The Paisley Caves complex is a system of four caves in an arid, desolate region of south-central Oregon, United States north of the present-day city of Paisley, Oregon. The caves are located in the Summer Lake basin at 4,520 feet (1,380 m) elevation and face to the west in a ridge of Miocene and Pliocene era basalts mixed with soft volcanic tuffs and breccias, from which the caves were carved by Pleistocene-era waves from Summer Lake. One of the caves may contain archaeological evidence of the oldest definitively-dated human presence in North America. The site was first studied by Luther Cressman in the 1930s.