The Dragon Kingdom

The dragon kingdom is a pocket dimension that is closely guarded, as it is the dragon's one true fortress. Only dragons can enter the kingdom, and it's not exactly the type of thing one does daily, unless their nest is in the kingdom. The entryway is a portal at the center of the cluster of Haven Clouds. Each dragon who enters is transported to their section of the kingdom. Once there, they can travel to other portions, every place except for the palace and its grounds. The only people allowed there are the royal family, the royal counselors, and guards. 
There are six different sections of the kingdom: the palace and grounds, and sections for Amnirclaws, Ignisclaws, Arborclaws, Duskclaws, and Dawnclaws. The weather varies from section to section. The sections are mainly a spot to practice flying and to have fun with friends and family, though there are places for nests. 
The Amnirclaw area is completely underwater. There are underwater caverns, underwater fields, underwater kelp forests, and more. It is the only area of the kingdom with naturally-occurring wildlife, in this case: the fish.
Ignisclaws get a range of volcanoes. They can withstand the intense heat, and it's actually healthy for them to take a dip in the lava every now and again. The weather is generally sunny and dry, though occasionally there will be rains.
Arborclaws reside in a huge landscape of lush jungles and forests. The trees are spaced widely so there's enough room for them to weave in and out of the forest.
Both Duskclaws and Dawnclaws have a similar section, with clouds and sky. They can have any weather, though in the Duskclaw region, it's always night, while for the Dawnclaws it is perpetually daytime.
The Dragon Kingdom is the largest and grandest pocket dimension in this world. It is capable of housing the entire dragon population, and that is why it is guarded so carefully.

Type

Dimensional, Pocket