Passport stamp in the context of "Visa policy of Japan"

A travel document is an identity document issued by a government or international entity pursuant to international agreements to enable individuals to clear border control measures. Travel documents usually assure other governments that the bearer may return to the issuing country, and are often issued in booklet form to allow other governments to place visas as well as entry and exit stamps into them.

The most common travel document is a passport, which usually gives the bearer more privileges like visa-free access to certain countries. While passports issued by governments are the most common variety of travel document, many states and international organisations issue other varieties of travel documents that allow the holder to travel internationally to countries that recognise the documents. For example, stateless persons are not normally issued a national passport, but may be able to obtain a refugee travel document or the earlier "Nansen passport" which enables them to travel to countries which recognise the document, and sometimes to return to the issuing country.

A passport is a formal travel document issued by a government that certifies a person's identity and nationality for international travel. A passport allows its bearer to enter and temporarily reside in a foreign country, access local aid and protection, and obtain consular assistance from their government. In addition to facilitating travel, passports are a key mechanism for border security and regulating migration; they may also serve as identity documents for various domestic purposes.

State-issued travel documents have existed in some form since antiquity; the modern passport was universally adopted and standardized in 1920. The passport takes the form of a booklet bearing the name and emblem of the issuing government and containing the biographical information of the individual, including their full name, photograph, place and date of birth, and signature. A passport does not create any rights in the country being visited nor impose any obligation on the issuing country; rather, it provides certification to foreign government officials of the holder's identity and right to travel, with pages available for inserting entry and exit stamps and travel visas—endorsements that allow the individual to enter and temporarily reside in a country for a period of time and under certain conditions.

There are over 50 places where people may cross the Mexico–United States border. There are also at least eight rail crossings and two ferry crossings along the border. Several large border cities have multiple crossings, often including one or more that bypass the center of the city and are designated for truck traffic. Several crossings have also been closed by the governments of either Mexico or the U.S., or both.

On the U.S. side, the Department of State assigns a three-letter Port of Entry code to each crossing. This code is included on the passport entry stamp or parole stamp one receives when crossing into the U.S. Note that one code may correspond to multiple crossings.

The Polish–Ukrainian border is the state border between Poland and Ukraine. It has a total length of 529 km (329 mi) to 535 km (332 mi) (sources vary).