Social Security numbers (SSN) are used to report a person's wages to the government and to determine eligibility for Social Security benefits. SSNs are tied to individual Social Security Accounts. They are represented by Social Security Cards.
Many non-U.S. citizens need Social Security Numbers if they are receiving funds from Fermilab (such as a salary or per diem), or to do business with certain private companies such as banks.
Non-U.S. citizens who are not employed in the U.S., or who do not hold a U.S. immigration status that entitles them to live here for a long time are not eligible to apply for SSNs. These include individuals visiting the U.S. in B-1 status as a business visitor, B-2 tourist status, or under the Visa Waiver program.
Non U.S. citizens visiting the U.S. for employment (such as those holding H-1B, TN or O-1 status) generally must apply for SSNa, as their employers will require the SSN to report earnings to the U.S. government. Non U.S. citizens visiting the U.S. for research or school (such as those holding J-1 or F-1 status) may apply for SSNs if they also are employed.
The application for a SSN is free. The SSN application may be submitted only while the applicant is lawfully in the U.S. General information about Social Security is here. Individuals who are employed can obtain further information about SSNs here. Individuals who are holding F-1 or J-1 status can obtain further information here.