[2] It is native to the southern Australian Capital Territory, particularly found in the Namadgi National Park on the summit of Sentry Box Mountain.

The collection took place at the summit of Sentry Box Mountain in the Namadgi National Park, Australian Capital Territory, at an elevation of 1,720 m (5,640 ft), where it was found growing on sheltered granite surfaces.

[1] Rhizocarpon vigilans has a crustose, epilithic (growing on the rock surface) thallus that is pale to medium grey, sometimes greenish-grey, and forms colonies up to 2 cm wide.

The cortex is poorly defined, and the medulla is white and reacts positively to iodine staining, turning a deep blue, a key indicator of its chemical makeup.

The apothecia (fruiting bodies) of this species are numerous and dull black, initially plane but typically becoming convex as they mature, measuring between 0.30 and 0.77 mm in diameter.