Matsyapurana 122.36

122.36

tāsāṃ tu nāmadheyāni parimāṇaṃ tathaiva ca
na śakyaṃ parisaṃkhyātuṃ puṇyāstāḥ sariduttamāḥ //

It is very difficult to enumerate and give proper measurements of all those rivers and rivulets. They are all sacred. The people of the janapadas who drink their waters get happiness. Śântabhaya, Pramâda, Śiva, Ânanda, Sukha, Kṣemaka, and Nava; such are the seven janapadas situated there, where all the rules and customs (Âchâra) of Varṇa and Âśrama are observed.—36-38.