Tallgrass

HeartGold Generations areas

Rock Tunnel

Leads to Route 10

Grass

PokémonWhenLevelChance
DiancieAny time8–1439%
DialgaAny time10–1632%
RegisteelAny time8–1629%

Rock Smash

PokémonWhenLevelChance
GeodudeAny time12–21100%

Items

ElixirTM56Revive · hiddenAntidote · hiddenIronPP UpReviveOval StoneTiny Mushroom · hiddenBig Mushroom · hidden