People keep saying you find Bagon in the smallest room in metor falls,..

Go into the main foyer, go up the waterfall, in the hole, down the ladder, head for the ladder to the north on the floor below, go down the mudslide and bank left to the ladder by the small pond, Surf up the aquifer on the floor below, go in the hole.

Here. I hope this helps...

When you get waterfall go back to Meteor Falls. Go across the bridge and up the waterfall. Then go through the door. In this rom go to the right and up to a ladder. Now go down alittle and to the right. Do not go up the stairs. Go up. (You can go up the stairs and down this ladder to get to battle Steven.) After you go up you should see a ladder. Use it. Now go up. There is a trainer couple. Battle or avoid them and head up. When you reach the top of the stairs there should be a trainer. You unfortuantly have to battle him. Once that is done you must jump down the ledges. This is where it gets tricky. You must stay to the right as much as possible. After 6 jumps if you stayed right there will be a break. If you take the next jump you have start over from the trainer couple. When you get to this break go to the right and take the ladder. Now go down the stairs and surf up to the door. You are now in a room with water surf across it and there you go. (You will know that you are in the right spot because there should be a TM 02 (Dragon Claw.) It will take a while to find a Bagon. I suggest you bring an escape rope with you. Otherwise you have to back track.

He is in the smallest room,at the end, he is kinda rare when you entert the room you will find tm dragon claw and most you could find are solrock, Bagon in the wild is mostlikely to be level 25.

Well I haven't made a walkthrough but I can try to explain it.
Well obviously you go into Meteor Falls and you go up the waterfall. Go through the door and then down the stairs. From there, go north and go up the stairs. I believe you should be in a room with an old couple and a dragon tamer? So pass the old couple, go up the stairs, pass the dragon tamer, and when you go down the ledges stay as far left as possible. If you did so, you should end up near stairs. Go down them. From there go down [obviously] and use surf. Follow the path of water until you see a first glance of land. Go there and go through the door. Once again use surf and go to the end of the room. Once you're on the other side, run around on the land and you should eventually run into some Bagon.

Go into the main foyer, go up the waterfall, in the hole, down the ladder, head for the ladder to the north on the floor below, go down the mudslide and bank left to the ladder by the small pond, Surf up the aquifer on the floor below, go in the hole.

Well, simpley go into Meteor Falls, go to the complete end, were you will be in a room were there is a small pad of land and then a large patch of water then another small patch of land, go to the second patch of land across the water and walk around for a bit of time, it might take time because Bagon is more rare in Emerald.