Human migration involves the movement of people from one place to another with intentions of settling, permanently or temporarily, at a new location (geographic region). The movement often occurs over long distances and from one country to another, but internal migration (within a single country) is also possible; indeed, this is the dominant form of human migration globally. Migration is often associated with better human capital at both individual and household level, and with better access to migration networks. Age is also important for both work and non-work migration. People may migrate as individuals, in family units or in large groups. There are four major forms of migration: invasion, conquest, colonization and emigration/immigration.
Persons moving from their home due to forced displacement (such as a natural disaster or civil disturbance) may be described as displaced persons or, if remaining in the home country, internally-displaced persons. A person who seeks refuge in another country can, if the reason for leaving the home country is political, religious, or another form of persecution, make a formal application to that country where refuge is sought and is then usually described[by whom?] as an asylum seeker. If this application is successful this person's legal status becomes that of a refugee.
In contemporary times,[when?] migration governance has become closely associated with state sovereignty. States retain the power of deciding on the entry and stay of non-nationals because migration directly affects some of the defining elements of a State.