At what level does Lairon evolve in Pokemon?

Lairon evolves into Aggron at level 42. In addition, this Pokémon can be evolved further into Mega Aggron through the use of a mega stone.

Obtain a Lairon by catching one along Route 18 in "Pokémon X," trading with in-game characters or evolving it from a Aron. This line of Pokémon is classified as steel and rock type. This line also has access to several potent abilities, including Sturdy, which makes the Pokémon immune to one-hit knockout moves. Lairon is also immune to the recoil damage caused by moves such as Takedown through use of the ability called "Rock Head."