Immigration law refers to the national statutes, regulations, and legal precedents governing immigration into and deportation from a country. Strictly speaking, it is distinct from other matters such as naturalization and citizenship, although they are often conflated. Immigration laws vary around the world, as well as according to the social and political climate of the times, as acceptance of immigrants sways from the widely inclusive to the deeply nationalist and isolationist. Countries frequently maintain laws which regulate both the rights of entry and exit as well as internal rights, such as the duration of stay, freedom of movement, and the right to participate in commerce or government.
National laws regarding the immigration of citizens of that country are regulated by international law. The United Nations' International Covenant on Civil and Political Rights mandates that all countries allow entry to their own citizens.
To control immigration, many countries set up customs at entry points. Some common location for entry points are airports and roads near the border. At the customs department, travel documents are inspected. Some required documents are a passport, an international certificate of vaccination and an onward ticket. Sometimes travelers are also required to declare or register the amount of money they are carrying.