The 7th badge is in mahogany town.
In Cinnabar Island, south of Pallet Town.
In Pokemon Red, the fifth badge is possessed by the Poison-Type Koga. The badge is named Soul Badge. It lets you use Surf outside of Battle.
The 7th badge.
Go to the Pokemon league.
beat the 7th badge, and you will be taken to it
The 7th badge is in mahogany town.
In Cinnabar Island, south of Pallet Town.
The Cascade Badge
You go to Viridian City ( the first town after Pallet Town ) and fight Giovanni for the 8th. Badge. ( He use Ground Pokémon )
In Pokemon Red, the fifth badge is possessed by the Poison-Type Koga. The badge is named Soul Badge. It lets you use Surf outside of Battle.
The 7th badge.
Go to the Pokemon league.
You go to get your 7th Badge in Mossdeep City.
The 7th badge
The 8 badges for Pokemon Red are: Boulder Badge, (Brock) Cascade Badge, (Misty) Thunder Badge, (Lt. Surge) Rainbow Badge, (Erika) Marsh Badge, (Sabrina) Soul Badge, (Koga) Volcano Badge, (Blaine) and Earth Badge. (Giovanni)
You will get the 7th Badge which is the Volcano Badge from Blaine, the Gym Leader of Cinnabar Island however you will need to receive the Key from within the Pokémon Mansion before you can unlock the Gym's locked door.