Minecraft wiki entry for Spawner_traps, associated text: Dungeons are found when tunneling or exploring caves and mineshafts. They appear to spawn in random places, but almost always underground, usually at the Y=30 to Y=60 range. Finding dungeons without mods, cheats, or external programs is mostly attributed to luck and some know-how. While exploring, some tricks can be used to help detect dungeons. Gravity blocks like sand and gravel in a neat square may cover a spawner and is easily visible in deserts if spawned near the surface. Hearing or seeing a group of single-type mobs while caving could mean a spawner is nearby. Lastly, mossy cobblestone or normal cobblestone naturally spawning away from lava, is a dungeon, unless it is in a jungle biome, where it can also be a jungle temple.