You are authorized to remain in the United States through the expiration date on your most recently issued I-94 record. In most cases, the expiration or “admit until" date on Form I-94 will list a specific status end date.
If you are in F-1 or J-1 status, as long as your most recent Form I-94 lists the admit until date as “D/S" (duration of status) and you have a valid enabling document (Form DS-2019 or Form I-20), you are permitted to stay in the United States until the end date on your enabling document. If your DS-2019 or I-20 is renewed, you can stay until the new end date.
Certain immigration statuses have a “grace period," which allows you to remain in the United States – but not work – for a limited period at the end of your time at NIH. For example, J-1 Exchange Visitors have an automatic 30-day grace period at the end of their NIH program. Grace periods are not automatically granted for all immigration statuses. Contact DIS if you have additional questions.
You must follow all the rules and regulations associated with your status. If you violate any of these regulations, you may be considered “out of status", meaning you no longer have a lawful basis for being in the United States.