Chapter 78 of the Varaha Purana offers many relevant details about Manasa lake:
1-8] I shall now tell you about the four great mountains
and about the lakes in them, which are beautiful, from which
blow the gentle and sweet-smelling breeze, which have rivers
flowing out of them, each of which have nine regions frequented
by the celestial couples, which are full of gems and sacred spots,
which always sound with waterfalls, which are full of lotuses,
lilies, and other beautiful plants.
9] The lake in the eastern mountain is Arunoda, the one in
the southern is Manasa, the one in the western is Asitoda and the
one in the northern is Mahabhadra. All these are full of lilies
of various colours.
13] The mounts around Manasa, I shall now enumerate.
14-16] They are Trisikhara, Sis'ira, Kapi, Satamaksa, Turaga, Tamrabha, Visa, Svetodana, SamQla. Sarala, Ratnakrtu.
Ekamula, Mahasriiga, Gajamula. Savaka Pancasaila, Kailasa
Lines 1 through 8 are particularly evocative.