A port of entry is a place where one may lawfully enter a country. It typically has a staff of persons who check passports and visas and inspect luggage to assure that contraband is not imported. International airports are usually ports of entry, as are road and rail crossings on a land border. Seaports can be used ports of entry only if a dedicated customs presence is posted there. The choice of whether to become a port of entry is up to the civil authority controlling the port; In the USA, for example, Los Angeles and San Diego are ports of entry whereas Newport Beach is not.
At some Ports of Entry, immigration procedures are carried out by the armed forces rather than specific inmmigration officers. However customs is still carried out by customs officers.
On some borders the concept of a port of entry does not exist. Travellers may cross the border wherever and whenever convenient. In some cases this may be restricted to citizens of specific countries and to travellers who are not carrying goods over the customs limits; other travellers may only cross the border at designated border crossing during its opening times.