Nidoran♂ locations — where to catch

In Sinnoh (Diamond, Pearl & Platinum)

• Route 201 — Walk

In Johto & Kanto (HeartGold & SoulSilver)

• Johto Safari Zone — Walk
• Route 35 — Walk
• Route 36 — Walk

In Kanto (FireRed & LeafGreen)

• Route 3 — Walk
• Safari Zone — Walk

In Johto & Kanto (Gold, Silver & Crystal)

• National Park — Walk
• Route 35 — Walk
• Route 36 — Walk

In Kanto (Red, Blue & Yellow)

• Route 10 — Walk
• Route 2 — Walk
• Route 22 — Walk
• Route 9 — Walk
• Safari Zone — Walk

Other games (6)

• Brilliant Diamond / Shining Pearl (Gen 8): Route 201
• Sword / Shield — The Isle of Armor (Gen 8): Ballimere Lake, Frigid Sea, Frostpoint Field, Giant's Bed, Old Cemetery
• Let's Go, Pikachu! / Let's Go, Eevee! (Gen 7): Kanto Route 10, Kanto Route 22, Kanto Route 23, Kanto Route 9
• X / Y (Gen 6): Kalos Route 11
• Black 2 / White 2 (Gen 5): Hidden Grotto, Unova Route 2
• Black / White (Gen 5): White Forest

Nidoran♂ — full Pokédex entry