MacDougal Crater is about a mile (1.6 km) in diameter from rim crest to rim crest and 131 m in maximum depth. The Sierra Pinacate in the distance consists of a large shield volcano, Volcán Santa Clara, plus the numerous cinder cones built on the surface of the shield. Dan Lynch (1981) reported that the last eruption of the old shield volcano itself occurred about 1.1 million years ago and produced a trachyte.

On March 20, 1701, Jesuit Padres Kino and Salvatierra, together with Spanish Captain Juan Manje, explored around the southwest base of Volcán Santa Clara and recognized the volcanic origin of the terrain (details in Gutmann, 2007). Ives (1942) noted that this apparently is one of the first, if not the first, reported identifications of an extinct volcano in North America.