We report for the first time the presence of 2 shrew species (Sorex altoensis and S. emarginatus) and 4 rodent species (Peromyscus merriami, P. schmidlyi, Reithrodontomys zacatecae, and Sigmodon leucotis) in the state of Nayarit, Mexico, as well as the occurrence of P. carletoni and P. schmidlyi in Jalisco and Zacatecas. We extend the known distribution range of the squirrel Sciurus aureogaster to northern Nayarit and report the presence of 2 subspecies of P. eremicus and 3 of Neotoma mexicana in near sympatry. We also confirm the presence of Tlacuatzin sinaloae and P. micropus in Nayarit. Finally, we document the presence of Dasypus novemcinctus in the highlands of the Sierra Madre Occidental in Durango; these are the first records of the nine-banded armadillo in Durango in 57 years. Our results highlight the importance of continuing biological surveys and inventories in the least-explored areas of Mexico.