Akodon spegazzinii is found in northwestern Argentina, in the provinces of Salta, Catamarca, Tucumán, La Rioja, and Mendoza, at altitudes of . Although its main distribution is in the northern provinces of Salta, Tucumán, and Catamarca, there are also scattered records from the more southern provinces of La Rioja and Mendoza, where it is likely restricted to patches of wet habitat. "Akodon alterus" has been reported from Jujuy, but this record was likely based on misidentified specimens of "A. boliviensis", and records of "Akodon spegazzinii" from Jujuy were based on misidentified "A. sylvanus". "Akodon spegazzinii" is known from a paleontological site in
Catamarca Province low humidity and high solar radiation. Before the arrival of the Spanish conquest, most of today's Catamarca was inhabited by the Diaguitas indigenous people, including the fierce Calchaquí tribe. In 1558 Juan Pérez de Zurita founded "San Juan de la Ribera de Londres", but since it was constantly under attack by indigenous people its population remained small; it was re-founded several times at new sites with new names. The sixth foundation was by Fernando de Mendoza Mate de Luna on July 5, 1683, with the name "San Fernando del Valle de Catamarca". When the Viceroyalty of the Río de la