Stronghold

A stronghold is a rare underground structure in the Overworld, and is the only place where an End portal can be found. Strongholds can be located by using an eye of ender.

Strongholds generate at any Y level, mostly underground, and prefer to generate in biomes above sea level, but generate underwater if necessary. Strongholds may generate at bedrock level, cutting the bedrock.

Most parts of the stronghold can be overwritten by caves, ocean monuments, ancient cities, mineshafts, fossils, amethyst geodes, trial chambers, and monster rooms; but it is rare for the End portal to be replaced, which would force a player to find one of the other strongholds, as a portal can be activated only with all 12 End portal frames present. Canyons do not overwrite strongholds; rather, a stronghold can occasionally be found exposed by a canyon.