One of the five mountains round Rājagaha and one of the beauty-spots of the city. DN.ii.116 There was, on one side of it, a black stone called the Kāḷasilā. This was a favourite haunt of the Buddha and the members of the Order. There Dabba Mallaputta is asked by monks to provide for them accommodation. Vin.ii.76 Vin.iii.41
It was also the scene of the suicide of Godhika and Vakkali. SN.i.121 SN.iii.121f.
In the Cūḷa DukkhakKhaṇḍa Sutta it is said that a large number of Nigaṇṭhas lived at Kāḷasilā, never sitting down, undergoing paroxysms of acute pain and agony, following the teachings of Nigaṇṭha Nāṭaputta. The Buddha questioned them as to their practises and preached to them the above-mentioned Sutta, which he afterwards repeated to Mahānāma. MN.i.91ff.
Once when the Buddha was dwelling at Kāḷasilā, he sang the praises of Rājagaha, giving Ānanda a chance, if he so desired, of asking him to live on for a kappa; but Ānanda did not take his opportunity. DN.iii.116
The books refer to several other visits of the Buddha to Isigilapassa. During one of these visits he heard Vaṅgīsa’s high eulogy of Moggallāna. SN.i.194 Thag.1249ff.
In the Isigili Sutta MN.iii.68–71 the Buddha is represented as saying that while the other mountains round Rājagaha—Vebhāra, Paṇḍava, Vepulla and Gijjhakūṭa—had changed their old names, Isigili retained its former name and designation.
Five hundred Pacceka Buddhas once resided in Isigili for a long time; they could be seen entering the mountain, but once entered, there was no more sign of them. Men, observing this, said that the mountain swallowed up the sages and so it came by its name of Isigili (“Gullet of the Sages”).