it is Mauville gym
Head to lavaridge town for your next badge.
Fortree City ( Feather Badge ) Leader's pokemon: Altaria, Swellow, Skarmory, Pelipper
At Sootopolis City.
Go North to Mauville City
If you mean the third gym, then it is located in Mauville City. In which the gym leader is an electric type which can easily be defeated by a ground type pokemon.
the first badge in in rusboro city sorry for spelling its at the end of the forest
It is in fortree city
If you mean Balance Badge in Petalburg City. You need to go in Fortree City. Simple huh?
Somewhere near Mauville
on mauville city
You get it in Sootopolis city. If your playing Ruby or Sapphire. You would be fighting Wallace. In Emerald, You fight Juan.
With the seventh badge in Pokemon Ruby version, you can control caught or traded Pokemon up to level 70.