The fastest way to farm Iron Ore
Iron Ore is densest in the Rocky Ridges mines, and eating a Hamburger Steak before mining lets Rock Smash break tougher ore veins faster.
Rock Smash iron ore blocks in the Rocky Ridges mines, both on the surface layer and in the deeper Rocky Ridges Underground caves — both hold iron veins alongside copper and gold. The Abandoned Mine Shaft in the southwest corner of Rocky Ridges is called out repeatedly as the richest single ore location in the region, with a pre-laid rail line marking a run of dense veins.
Eat a Hamburger Steak before a mining trip; it powers up Rock Smash so it breaks tougher ore blocks in fewer hits, which matters once you're clearing whole walls of ore rather than single blocks. A practical routine is to walk each tunnel once to map it out, note where the ore clusters are, then come back with an empty bag and clear them in one focused pass instead of stopping to unload constantly.
If you'd rather not mine at all, a Crush-specialty Pokémon such as Onix or Graveler can be set up to generate ore passively over time, and Nonburnable Garbage collected on Bleak Beach can be traded to a Recycle-specialty Pokémon for Iron Ore directly, sidestepping the mines entirely.
Related: Iron Ore, Iron Ingot, Nonburnable Garbage
Regions: Rocky Ridges, Rocky Ridges (Underground), Bleak Beach