What is your level and are you horde or alliance? It makes a difference...
The best way to find your answer is probably to type "iron deposit" in the search box on the left and find an area you know your character can survive in from the list that comes up. Then check the map for mining locations.
For my lvl 32 paladin, the best places I've found are the Angerfang Camp and the cave in Raptor Ridge in the Wetlands, and once you get the flight path from Astranaar, Stonetalon Peak is also good. Both of these are favorite ganking places for horde on my server though, so it can get a bit frustrating.