Is there a "best" elevation to find Iron veins?

[Lovecraft]

I typically go all the way to bedrock before I start branching out and I'm wondering if I'm shooting myself in the foot and missing the lion's share of Iron that may quite possibly be just 20-30' above me... so, is Iron (and the other mine-ables) randomly spread throughout the substrate or are there levels/depths where one is more likely to find these things? (kinda like you wanna be around lvl 12 if your looking for Minecraft diamonds).

[YamaKami]

Below the soil (not in a desert biome) anywhere in the stone level. Caves make it much easier to find in addition to that. In the desert you will find oil shale, but not Iron however. So keep to non-desert biomes if iron is the goal.

[Ch53dVet]

I'm currently living in a mid-sized town with a good mix of residential and buisness properties.
I always sink a mine shaft straight to the bottom, from my basement, then I tunnel to the nearest street. (keeping my base structural integrety damage to a minimum) I mine underneath the streets for underground access to all the buildings, you'll find more than enough materials at the bedrock level to take away any notion of better veins above you, and none of the veins I find are ever ore specific it's all the ores clumped together.

[Argerodes]

i have found them very often just under the soil when i hit rock in the plains biomes - often while digging moats or trenches. when i do, they go on and on. i made a mine on a seam on a road in the plains there a patch of iron showed on a cliff and it was paydirt forever.

[Hashshashin]

I've always used two methods, tunnel straight down or tunnel sloping, straight down is very hit and miss but a slopping tunnel down 3x3 is the most productive for finding ore spots. I almost always head for the maple biome as you will find everything except shale under it and usually plenty of ore. If you think you've mined out a spot, always cut back the rock 3 to 4 blocks past the ore as you might, and I usually do, hit more. Once we used to mine out balls of ore, now it's more like a ben and gerrys mixed ice cream but you'll also get rock mixed in so you get pockets of rock in ore spots, hence you need to dig back/under those extra blocks of stone just to be sure before you move on. Above all the most important thing is to sacrifice a fluffy kitten or puppy to the randomgod and hope it's enough for it to generate a nice amount of ore in the first place, the great randomgod is sometimes a complete sh!te though. Happy hunting, hermit out...

[Loudog]

The snow biome is the iron motherlode.