It is found in Antafondro Classified Forest Special Reserve in northern Madagascar.

The name margotmarshae was chosen in honor of Margot Marsh, who made generous lifetime contributions to primate conservation initiatives in many different countries.

Upon her death in 1995, the Margot Marsh Biodiversity Foundation was founded to continue supporting her efforts to help safeguard the future of threatened primates.

[3] Margot Marsh's mouse lemur is found in the Antafondro Classified Forest Special Reserve, south of the Andranomalaza River and north of the Maevarano River in the Antsiranana Province of Madagascar.

[3] The northern end of Margot Marsh's mouse lemur's range is bordered by the range of the Sambirano mouse lemur (M. sambiranensis), forming a significant species barrier between it and its genetically closest sister taxon, Claire's mouse lemur (M. mamiratra), farther to the north.