Working in the United States
Under US federal law, the employment and/or compensation of persons who are not U.S. citizens is governed by the specific immigrant or non-immigrant visa category or status held by the individual. Under the Immigration and Reform Control Act of 1986 (IRCA), any employer not in compliance with these regulations is subject to severe fines and penalties.
There are essentially two types of visas: immigrant and non-immigrant.
Immigrant visas are given to those individuals who have applied and been granted permission to reside permanently in the United States. Foreign nationals who hold immigrant visas are entitled to live and work permanently in the United States and may work at any job for any employer and receive compensation for services under the same laws as a U.S. citizen.
There are other foreign nationals who are not permanent residents, but are authorized to work in the U.S. at any job or position, with any employer because of their immigration status. They might be conditional or temporary residents, refugees or asylees, fiancés or fiancées of U.S. citizens, foreign nationals who have been granted Temporary Protected Status (TPS), or other individuals who have been granted employment authorization by the US Citizenship and Immigration Services (USCIS, formerly known as the INS) under the terms of their visas. Employment in these cases is limited to the length of time indicated on the employment authorization document (EAD).
Non-immigrant visas are given to those individuals who intend to come to the United States for a temporary period of time. They may be here as students (F-1, J-1 or M-1), as temporary workers (H-1, H-2, H-3, L-1, O-1), as participants in international cultural programs (Q), as entertainers or athletes (P-1, P-2, or P-3), as exchange visitors (J-1) ,as diplomats (A) or representatives of foreign governments (G), as investors (E), religious workers (R), as visitors for tourism (B-2) or short-term business purposes (B-1). There are currently more than 40 different types of non-immigrant visas.
By far the majority of foreign nationals who enter the U.S. every year do so on non-immigrant visas. In most cases, compensation for individuals on non-immigrant visas is severely restricted. Most will not be authorized to receive compensation of any kind from the University System unless they have been given special permission by the USCIS to do so.
Individuals who have been granted the right to live in the U.S. permanently are called Permanent Residents and are issued an Alien Registration Card commonly referred to as a "Green Card". Permanent Residents are permitted to work in the U.S. without restrictions. They may work at any job for any employer. As proof of their right to work in the U.S. they need only present their valid "Green Cards" (which are not green in color).
Sometimes a person who has been granted residency in the U.S. will not yet have received their Green Card. For purposes of employment these individuals may present a stamp in their passport as evidence that they have been approved for permanent residency. This is called an I-551 stamp and serves as proof of authorization to be employed. The I-551 stamp will contain a nine digit number beginning with the letter A and will probably read "Processed for I-551 temporary evidence of lawful admission for permanent residence. Valid until (date) employment authorized".
The vast majority of foreign nationals enter the United States on non-immigrant visas. The type of non-immigrant visa on which an individual enters determines whether or not he/she is permitted to work or receive any form of compensation while in the U.S.
Authorization to be employed in the U.S. in a non-immigrant visa status is quite limited. Most visas which authorize employment in the U.S. restrict it to a specific employer and a specific position. In order to employ the foreign national, an employer is required to file an application (called a petition) with the USCIS to request permission to employ the particular foreign worker. The foreign worker may not begin employment until the USCIS indicates approval of the employer's request. The foreign worker is only permitted to work for the petitioning employer and is generally prohibited from working for, or receiving compensation from, any other entity.
Although Canadian citizens do not need to obtain a visa to enter the United States, they are subject to the same employment and compensation laws as citizens of all other countries.