There isn't one. Mt. Coronet is an area in sinnoh, the fourth generation.
in the center of sinnoh
you git him on mount cornet
You find it at mount cornet.
in mount cornet with honey
Sprint
when you get your seventh badge and you will head for mount cornet
Mount Cornet on Hearthome city side
mt. cornet
in mount cornet with a good rod
mount cornet
catch dialga and/or palkia
neverland!