It is endemic to the Peninsular Malaysia and has only been recorded from its type locality in the Endau-Rompin National Park, Johor.

[1][5] However, I. gollum is genetically so close to Ingerophrynus divergens that its validity as a distinct species can be questioned.

[2][4] Three adult males in the type series measure 27–28 mm (1.06–1.10 in) in snout–vent length; females are unknown.

[2] The type series was collected in closed-canopy lowland forest (46 m (151 ft) above sea level) in the early evening following brief periods of afternoon precipitation.

Outside the park, if it occurs there, its habitat is threatened by logging and agricultural expansion (especially oil palm plantations).