Corbet and Hill (1992) mention that Maxomys rats are often the most common rodent in the Southeast Asian tropical forest, from most of the Malay Archipelago to Sulawesi, Palawan and Borneo.

According to Payne et al. (1985) this species lives in primary or secondary forest and tends to favour sandy and lowland sites.

M.rajah is a common species but Yasuda et al. (2000) reported that very little is known about the ecological features of Maxomys rats.

M. rajah is medium in size where the upperparts are brown, darker in the midline, with numerous stiff gray-brown spines.

The immature Red Spiny Rats, M. surifer is similar M. rajah and quite difficult to distinguish.