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
Formosa Peak of Ken Webb, a 72-year-old experienced hiker from Plettenberg Bay, who fell while descending the mountain. Formosa Peak Formosa Peak or Peak Formosa is the highest point of the Tsitsikamma Mountains, a coastal range located along the Garden Route in South Africa, and forming part of the Baviaanskloof Mega Reserve. The peak was first mapped in 1576 during a voyage by the Portuguese navigator and cartographer, Manuel de Mesquita Perestrelo, when his ship put in at Plettenberg Bay, which he named "Bahia Formosa" or "beautiful bay". The peak, which is visible from the bay, had been named "Formosa" by the