Where to find Pokémon in Johto & Kanto at Blackthorn City (Pokémon HeartGold & SoulSilver)

Pokémon at Blackthorn City

• Poliwag — Good Rod, Old Rod, Super Rod
• Magikarp — Good Rod, Old Rod, Super Rod, Surf

Pokémon HeartGold & SoulSilver interactive map (Johto & Kanto)