A large lake below the Vebhāra mountain, outside Rājagaha. The lake was cool, but the stream flowing from it, also called Tapodā (Vin.iii.108; iv.116f; DA.i.35; UdA.110), was hot. Around it was the Tapodārāma.
It is said (SA.i.30f; Sp.ii.512) that the water of the river was hot because it flowed between two Lohakumbhi-nirayas, which existed under Rājagaha. The lake was the playground of the Nāgas who dwelt at the foot of the Vebhāra mountain. Monks and recluses were evidently in the habit of going to the Tapodā to bathe in the hot springs.
Thus, we find Samiddhi being questioned by a deity as he dried himself after bathing in the Tapodā (S.i.8ff; M.iii.192ff; J.ii.56), and the Anguttara Nikāya (v.196f) records a discussion between Ananda and the paribbājaka Kokanuda, on the banks of the Tapodā, where they had gone to bathe.