It's in between Ecruteak city and Mahogany town (in the tall grass of course).
Hope I helped!
You can't take it you have to catch a mareep evolve it into a flaffy then evolve it again
Ampharos cannot be found in the wild. You must catch either a Flaffy or a Mareep and evolve that. (Level 30 from Mareep).
In Pokémon HeartGold, Flaaffy can be found at Routes 42 and 43. Additionally you can find and catch Mareep in Routes 33, 42 and 43 and the Safari Zone and then evolve Mareep at Level 15 which will cause Mareep to evolve into Flaaffy.
You can get Mareep on route 32 and flaffy on route 43
Mareep evolves into Flaffy a Lv 15 then into Ampharos at Lv 30.
go to route 2 and use the pokeradar the best way to catch it is to use a master ball.
To catch ampharos, you have to evolve Flaffy to level 30 and use cheat codes as well.
You can't catch Rotom in heartgold.
you can catch it after you had finished you're first pokedex,you can find it just before sunshore city, its not that common but it is there.
you cant catch him in heartgold you can only get him in soulsilver
After you beat the elite four go to the safari zone and look for a secret area towards the right this is the johto area why is it called that? Because loads of johto Pokemon like mareep roam around here, catch a mareep then train it and it will become a flaffy train it to level 36 to make it become a ampharos if that doesn't work use a thunderstone on flaffy.
You can't catch him in HeartGold. Only in SoulSilver. In HeartGold, you catch Kyogre in Embedded Tower. If you transfer either Kyogre or Groudon to the other game, you can catch Rayquayza