1. Ambalatthiká.-A royal park on the road between Rájagaha and Nálandá. It contained a royal rest-house (rájágáraka) in which the Buddha and members of the Order used to stay in the course of their journeying. It was on one such occasion that the Brahmajála Sutta was preached (Vin.ii.287; D.i.1). Buddhaghosa (DA.i.41-2) says that it was a shady and well-watered park, so called because of a mango sapling which stood by the gateway. It was surrounded and well guarded by a rampart, and its rest-house was adorned with paintings for the king's amusement.
It was one of the spots in which the Buddha rested during his last tour, and we are told that while there he discoursed to a large number of monks (D.ii.81; he remained there one night, UdA.408). But the most famous of the Buddha's sermons in Ambalatthiká seems to have been the Ráhulováda Sutta named Ambalatthika-Ráhulováda Sutta, because of its having been preached in the park (M.i.414ff). From the context it appears as though Ambalatthiká was within walking distance from the Kalandakanivápa in Rájagaha.
But see below (4) for a more probable explanation.
2. Ambalatthiká.-A park in the brahmin village Khánumata. The Buddha went there during one of his tours through Magadha. On this occasion was preached the Kútadanta Sutta (D.i.127). Buddhaghosa (DA.i.294) says the park was like the pleasance of the same name between Rájagaha and Nálandá.
3. Ambalatthiká.-There was a place of this name to the east of the Lohapásáda in Anurádhapura. Once when the Díghabhánaka Theras recited the Brahmajála Sutta there, the earth trembled from the water upwards (DA.i.131).
On another occasion King Vasabha heard the Díghabhánakas reciting the Mahásudassana Sutta, and thinking that they were discussing what they had eaten and drunk, he approached closer to listen; when he discovered the truth he applauded the monks (DA.ii.635).
The place referred to here was probably not a park, but a building which formed part of the Lohapásáda. In the Mahávamsa account (Mhv.xxvii.11-20) of the building of the Lohapásáda we are told that the plans were copied from the gem-palace of the goddess Bíraní. The central part of the palace was called the Ambalatthikapásáda. "It was visible from every side, bright, with pennons hung out."
Dutthagámani probably included a similar central part in the Lohapásáda. This view is strengthened by No. 4 below.
4. Ambalatthiká.-According to Buddhaghosa (MA.ii.635), the Ambalatthiká, in which the Ráhulováda Sutta of that name was preached, was not a pleasance, but a pásáda, a kind of meditation hall (padhánagharasankhepa) built in the outskirts of Veluvanavihára for the use of those who desired solitude. It is said that Ráhula spent most of his time there, from the day of his ordination as a seven-year-old boy.