Where do you get hm defog in FireRed?

You can't get HM Defog in FireRed.

Here's why:

* Defog wasn't introduced until Generation IV (Diamond/Pearl/Platinum). FireRed is based on Generation III (Ruby/Sapphire/Emerald).

* HM01 Cut is the only HM that affects the environment in FireRed. It removes obstacles like trees and rocks.

Let me know if you have any other questions about FireRed or Pokémon!