Finding Iron in 1.21 isn't particularly tricky, as Iron Ore is abundant at various levels. However, generates worlds and resources in a way that makes targeted resource mining viable. Anyone searching for vast quantities of Iron and Iron Ore should target specific Y Levels, focusing on areas below ground, to maximize their resource gain.
According to Minecraft Wiki, iron ore is generated at different elevation levels in the world, from Levels -64 to 320. However, when generating seeds, the game splits the world into chunks: segments that are 16 blocks high and 16 blocks wide. Ore generation in depends on chunks, and Iron Ore is much more common in certain chunks and levels.
Minecraft's Caves & Cliffs update is making some major changes to iron and gold ores making it more beneficial for players to mine them.
The best individual Level in 1.21 to farm Iron is Y Level 14 (Y = 14) and Y Level 232 (Y = 232). The levels right next to these specific numbers have a high chance of containing Iron as well, which happens to be a common material found in every biome. The only restriction to Iron is that it does not spawn in Y Levels 73 — 79, no matter how hard you look.
The game attempts to generate Iron Ore in different batches during world generation:
However, this doesn't mean you should focus on the higher levels where Iron Ore tends to be generated most often. Although mining mountains and cliffsides is a great way to find nodes of Iron Ore, many of the levels in the 80-384 range are empty sky with little to no actual terrain. As such, the best approach is to focus on those underground layers, similar to the approach you'd take when mining the best level for Diamonds.
You will find a lot of Iron Ore in the-24 to -56 range, where the game tends to generate bigger blobs of Iron Ore. These are the best levels for finding Iron consistently and in large quantities in It's worth noting that the game generates a lot of Iron Ore per chunk, so you shouldn't have trouble
Read more on screenrant.com