This category is for those facilities worldwide that are exclusively or primarily used to detain refugees, asylum seekers, deportees, and those accused of immigration violations, or that at one time or another have housed a significant population of immigrants for the purpose of adjudication or deportation. These are arranged by country, but note that sometimes a detention centre will be in one country to hold detainees who are trying to get permission to stay in another country; for example, detention of asylum seekers in Nauru to prevent them from getting into Australia.