If you will require additional time in the United States beyond your current status end date, it may be possible to apply for an extension of your status. It is important to understand the difference between your immigration status and your visa. To maintain your status in the US, you must have a valid I-94 card, and other document(s) that may be associated with your status (for example, a DS-2019, I-20, or I-797 approval notice).
The visa stamp in your passport does not need to remain valid for you to maintain status within the U.S. In fact, the expiration date of the visa is relevant for only one thing: entering (or re-entering) the United States. If your visa expires, you will need to apply for a new one in order to re-enter the country in the same status (there are some exceptions to this rule—see below for details). In many cases, it is possible to extend your current status within the United States beyond the expiration of your visa.
If you are in F1, J1, H1B, O1, or E3 status and Cornell University is the sponsor, you can find information on how to request an extension on the relevant page linked here:
If you are sponsored by another institution, please contact your sponsor to discuss an extension of status. If you are in TN status, the ISSO recommends making a new entry rather than attempting to extend your stay from within the country.
If you are in B1/B2 status, you can apply to extend your status in the US for up to an additional six months. To apply for an extension, please complete form I-539 (available on the USCIS website) and submit it according to the instructions. The ISSO does not offer assistance with this process. This option is not available for those on a visa waiver (WB/WT).
In order to apply for a new visa stamp, you will need to make an appointment at a US embassy or consulate. You can do this in your home country, in Canada, or at many other embassies or consulates around the world. It is not possible to renew your visa from within the United States.
For more information:
In some cases, it is possible to return to the United States from Canada, Mexico, or certain adjacent islands (mainly in the Caribbean region) with an expired visa, as long as your status within the US is valid. Learn more.
Depending on your status, you may have a grace period following the end of your status. During your grace period, you may travel within the United States or apply for a change of status (as long as no other rule prevents this). Those in F1 status have a grace period of 60 days. For J1 exchange visitors, the grace period is 30 days. For those in other statuses, there is no automatic grace period—but check the date on your I-94 card to see the last date in which you can legally remain in the country.