Naglok, or Nagaloka, is the world of snakes and is underground – beneath the Earth. As per Hindu Puranas there are seven worlds below the earth and the Naglok is the last one. Vishnu Purana states that Patal or the underworld is 70,000 yojanas below the earth. One Yojana is equal to 8 miles.
The seven worlds occupy 10,000 yojanas each. So Nagaloka is located nearly 130,000 yojanas below the earth.
Sage Narada has mentioned that Naglok is beautiful than heaven, or Swarg, the abode of Devas or Demi Gods. Sunlight does not reach the Nagaloka. Puranas mention that the place is lighted up with the light emitting from the Nagamani atop the fangs of the snakes.
Naglok was built by Mayan – the Asura Architect. There is no death, old age or diseases at the world of Nagas. The place is ruled by Vasuki.