The following is an explanation of the process for obtaining U.S. visas. A brief description is given for each type of nonimmigrant visa as well as the various immigrant visa categories.

Nonimmigrant Visas

Some 25 different classes of nonimmigrant visas are issued by Foreign Service Offices of the U.S. Department of State at U.S. Embassies and Consulates abroad. They are broadly classified below as nonimmigrant visas without work authorization, nonimmigrant "working" visas, and nonimmigrant investor visas. When granted, the visa is stamped into a valid travel document, usually a passport. The visa bears the issuance date, the expiration date, and the number of applications for admission at the U.S. border for which it is valid.

At the border, the U.S. Immigration and Naturalization Service ("INS"), has jurisdiction to admit the individual in the status for which the visa has been granted, and it does so by endorsing the admission slip (Form I-94) which is attached to the individual's passport, recording the date of entry, the status in which the individual is admitted, and the duration of his or her authorized stay. Future extensions of this stay are endorsed on the admission document, or noted on a newly-issued Immigration Service Form I-797.

Canadian citizens may, under certain circumstances, present themselves at the border with appropriate documentation to request admission under the various nonimmigrant visa categories without first obtaining visa stamps at a U.S. Embassy or Consulate. In addition, under a special program known as the "Visa Waiver Pilot Program", nationals of certain countries have been allowed to enter the U.S. as visitors without first obtaining a visa stamp.

Immigrant Visas

An individual seeking lawful permanent U.S. residency must obtain preference classification based any one of the following: