No, there are only 2 regions in Pokémon HeartGold, the Kanto region and the Johto region.
johoto or kanto regions
Johto and Kanto are the only accessible regions in HeartGold.
only 2
you cant
You cannot get to the Sinnoh region in Pokémon HeartGold, you can only travel around the Johto and Kanto regions. No additional regions are available in HeartGold.
heartgold has 2 regions
no only in heartgold and soulsilver versions
you can only go to kanto and johto
you can't. Pokemon heartgold and soulsilver versions only have two regions: johto and kanto.
You can't. The Old Château is in the Sinnoh Region. Only Johto and Kanto are accessible in Pokemon HeartGold (which is the most amount of regions so far!)
you get it after you have all the gym badges from kanto and johto regions.
You can go to Kanto in HeartGold and SoulSilver, but Hoeen remains a Ruby/Sapphire/Emerald exclusive continent.