Where can you find bagon?

You can find Bagon in the place where the team aqua or magma take the meteorite but it is quite hard to come across one, meteor falls I think it is called but you have to go there as part of the game any way.

Meteor Falls, where you find TM02 (Dragon Claw).

Go to Meteor Falls and go up the waterfall. Go up the stair case, jump down until you find a detour to the left. You will soon find an entrance to a small cave acroos a body of water. Inside wil be a small cave with a miniature lake separating to peices of land. Go to the top of the cave and search for wild pok�mon. He is slightly rare, so be patient.

PS. I advise you catch two and trade one for a Horsea in Pacifilidog.

PPS. Hope I helped!!

Well that is hard because I have never found bagon

It is at meteor falls {ground floor in the small room}