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
San Fernando del Valle de Catamarca founded until 1683, by Fernando de Mendoza y Mate de Luna. "Catamarca" comes from Quechua meaning "fortress on the slope". The city, which had only 8,000 inhabitants in 1882 and was reached by a railway line in 1888, grew very slowly, and the region remained poor even in the middle of the 20th century. This situation was exacerbated by nepotism on the part of the ruling Saadi family, before they lost political power in the 1990s. In spite of this, the province remains still politically unstable, and a large part of its population lives in precarious conditions. The warm semi-arid