A United States visa allows travel to the border of the U.S., whereas a Green Card (permanent resident card) is issued to an immigrant admitted to the U.S. as a permanent resident.
To enter the United States, a citizen of a foreign country must generally first obtain a U.S. visa. A visa allows travel to a port of entry or border crossing of the United States. The visa indicates that a consular official at a U.S. Embassy abroad has determined the traveler is eligible to seek entry for the specific purpose of the visa (for example, as a tourist or on business). At the border, the visa holder may be granted admission to the U.S. for a specified status and period of time.
There are two main categories of U.S. visas:
- Nonimmigrant visas - for travel to the United States on a temporary basis. There are more than 20 nonimmigrant visa types (Example: visas for medical treatment, or for journalists).
- Immigrant visas - for travel to live permanently in the United States. There are an even greater number of immigrant visa types (Example: spouse of a U.S. Citizen, or Employment-Based Immigrant Visas).
A foreign citizen wishing to live permanently in the United States must apply for an Immigrant Visa from a U.S. Embassy or Consulate abroad. Once obtained, the visa allows travel to a U.S. port of entry or border crossing. On admission to the U.S., the foreign citizen will become a permanent resident. They will subsequently be issued what is known as a Green Card.
A Permanent Resident Card, Form I-551 (formerly called an Alien Registration Card) is also known as a "Green Card" (the historic color of the card, although no longer in use). A Green Card holder is someone who has been granted lawful permanent resident status (may live and work) in the United States.