Vishnupurana 2.7.12

2.7.12

dhruvādūrdhvaṃ maharloko yatra te kalpavāsināḥ /
ekayojanakoṭistu yatra te kalpavāsinaḥ //

Above Dhruva, at the distance of ton million leagues, lies the sphere of saints, or Mahar-loka, the inhabitants of which dwell in it throughout a Kalpa, or day of Brahmá. At twice that distance is situated Janaloka, where Sanandana and other pure-minded sons of Brahmá, reside. At four times the distance, between the two last, lies the Tapo-loka (the sphere of penance), inhabited by the deities called Vaibhrájas, who are unconsumable by fire. At six times the distance (or twelve Crores, a hundred and twenty millions of leagues) is situated Satya-loka, the sphere of truth, the inhabitants of which never again know death.