Srimad Bhagavatam Canto 05, Chapter 24, Text 06

SB 5.24.6

tato ’dhastac chata-yojanantara iyam prthivi yavad dhamsa-bhasa-syena-suparnadayah patattri-pravara 
utpatantiti.
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Below the abodes of the Yaksas and Raksasas by a distance of 100 yojanas [800 miles] is the planet earth. Its upper limits extend as high as swans, hawks, eagles and similar large birds can fly.
Srimad Bhagavatam Canto 05, Chapter 24, Text 05
Srimad Bhagavatam Canto 05, Chapter 24, Text 07