In the United States, the discussion around non-citizens coming to the country usually revolves around permanent immigration. However, thousands of people from all over the world come to the U.S. each year through work visas. These offer a non-permanent legal status to foreigners who have a specific work purpose for being in the United States.

The following are some of the most commonly issue U.S work visas.

1. H-1B Specialty Work Visa. The H-1B visa is far and away the most popular. These are issued to foreign citizens with specialized skills, such as engineers, programmers, or scientists; this can also include, for example, teachers with a specialty not easily found among U.S. citizens. Applications are filed by U.S. employers on behalf of the employees they wish to bring to the country. If accepted, the H-1B allows workers to stay in the U.S. for up to six years—three years on the initial visa with a further three year extension.
There is a yearly cap of 85,000 on H-1B visas, 20,000 of which must be filed on behalf of individuals with a U.S. master’s degree or higher. As this is far below the number of H-1B applications received each year, other visa types are coming into more regular use.

2. L-1 Intra-Company Transfer Work Visa. The L-1 allows foreign nationals already employed by an international company to transfer to branches of their companies in the U.S. Visa holders must have worked for the company for at least one continuous year within the three years immediately preceding admission to the U.S. These visas are specifically for managers and executives. Self-employed foreign nationals may not receive an L-1 visa.

Like the H-1B, the L-1 has an initial length of three years. However, it can only be extended to a total of five years rather than six.

3. NAFTA Work Visa. Also known as a TN visa, this visa is similar to the H-1B. Applicants must have a higher education degree, be part of a qualifying profession, and have a standing job offer in the United States. This visa was designed as part of NAFTA specifically for Canadian and Mexican nationals; it allows them to live and work in the U.S. without competing for H-1B visas.

The other benefit to the TN visa is that, while it initially allows individuals to stay for three years, visa holders can extend their stay indefinitely as long as they meet TN status.
Please note that Canadian citizens may stay in the U.S. without a visa, as long as they have other appropriate documentation (see here). Mexican citizens must apply for a visa.

4. R-1 Religious Worker Visa. The R-1 visa allows foreign nationals to work in religious occupations in the U.S. The organization that employs the worker must meet one of three criteria: it must be a recognized non-profit religious organization in the United States, a religious organization authorized by a group tax exemption holder to use its group tax exemption, or a non-profit religious organization affiliated with a religious denomination recognized in the United States.

Furthermore, the occupation must primarily relate to a traditional religious function, be recognized as a religious occupation within the denomination, and be primarily related to carrying out the beliefs of the denomination. Most frequently these visas are given to ministers, but they can go to any foreign national whose job meets these criteria.
R-1 visas are granted for thirty months, which can be extended to a total of five years.

For those interested in further information United States visas, a list of both nonimmigrant and immigrant visa categories, and links to what is needed to qualify for those visas, can be found on the U.S. State Department website.