Where to find Butterfree in HeartGold & SoulSilver

Walk: Route 2 (10%, Morning, Day, Only in HeartGold), Viridian Forest (10%, Morning, Only in HeartGold), National Park (5%, Bug-Catching Contest, Before the National Dex, After the National Dex, Tuesdays)
Headbutt: Route 47 (30%, Special tree, Only in HeartGold), Ilex Forest (10%, Rare tree, Only in HeartGold)

• Ilex Forest — Headbutt
• National Park — Walk
• Route 2 — Walk
• Route 47 — Headbutt
• Viridian Forest — Walk

Butterfree in every game · Pokémon HeartGold & SoulSilver interactive map (Johto & Kanto)