I understand that the word "mainland" refers to the lands that take the largest portion of the territory. Then what do you call the territory that is isolated from the mainland?

Rebecca

I am unsure if there's a specific name for it, but most of the time we just call it by it's given name. For example, in the United States, Alaska and Hawaii are states but are not connected to the mainland. We just say Alaska and Hawaii. The same goes for our territories like Puerto Rico or Guam.