Fellhorn Gorge, Mossfell Confluence, Reveler's Road — 3 locations on the interactive map.
Celadon City, Route 10, Route 22, Route 23 — 4 locations on the interactive map.
Ecruteak City, Mt. Silver, Route 22, Route 28, Route 30, Route 31, Route 44, Violet City, Viridian City — 9 locations on the interactive map.
Poliwag → Poliwhirl (Level 25) → Poliwrath (Water Stone) → Politoed (Trade holding Kings Rock)