Robert's arboreal rice rat occurs in northern and central South America. In one study in the Amazon basin, it was recorded mainly in seasonally flooded forest and captured both on the ground and in the canopy.
The upperparts are tawny to fulvous brown, grading to ochre on the flanks. The underside ranges from white to grayish white, and the dark brown tail appears nearly naked at a glance but has fine hairs.
In a study along Brazil's Juruá River, 88% of samples came from várzea forest and few from second-growth edges. Captures were equal on the ground and in the canopy.
An extinction-risk assessment has not been added yet.