To get the sixth badge in Pokemon FireRed and LeafGreen, you will need a Charmeleon that knows Flamethrower, or a Wartortle that knows Surf. Next, you should have a Graveler that knows Magnitude, for the Ground-Type is stronger than the Poison. Also, bring a lot of Antidotes or Full Heals, just in case your Pokemon gets poisoned. It's also beneficial if you have a Psychic or Steel-Type Pokemon, since they're both good against Poison too. Poison-Type attacks won't affect Steel-Type Pokemon at all!
Fortree City ( Feather Badge ) Leader's pokemon: Altaria, Swellow, Skarmory, Pelipper
The sixth gym badge (the Marsh badge) is located at Saffron City's gym. It is in Gym Leader Sabrina's possession, so you have to defeat her to obtain it.
in gym durr
i haht Pokemon soulsilver so live with it itiet
Back in the 3rd town where your dad is hope this helps :)
leaf
Saffron city.
The sixth badgeno actually it the third badge
Fortree City ( Feather Badge ) Leader's pokemon: Altaria, Swellow, Skarmory, Pelipper
The sixth gym badge (the Marsh badge) is located at Saffron City's gym. It is in Gym Leader Sabrina's possession, so you have to defeat her to obtain it.
the sixth gym badge is the jet badge and the type they have are flying type hope this helps:]
in gym durr
i haht Pokemon soulsilver so live with it itiet
which game series
you go south from mount pyre
You first need to beat Giovanni at Silph co which is in saffron city once you do that you can go into the gym and receive your sixth badge from Sabrina.
You can only get the Sixth Badge from the Sixth gym leader. After defeating the Sixth gym leader, the gym leader will give you the Sixth Badge.