The Blue Nile patas monkey (also known as Heuglin’s patas monkey) was initially described in 1862 from a living species and a skin. It was initially a subspecies alongside the other Patas monkeys, In 2017 it was redefined as a separate species. In many ways, this is a good thing. While it is clear that these species are quite different, it is also likely to be easier to protect both species, now they are separate than it was while they were merely subspecies of each other.

It is restricted to the land between the Nile, and the great rift valley. Although it is currently only known from Ethiopia and Sudan, though it is thought that it may well also be found in the new country of South Sudan as well. Little museum species, and few records of the species in Ethiopia, which heavily suggests that it was never common in this country.

Recent moves to forcibly create villages, and the expansion of farms may well eradicate what little remains. Unfortunately, as much of its range is still so dangerous there is little studies done there, and as a result, this species is classified as data deficient.