Generally speaking, your non-immigrant visa status can be extended while you are in the U.S. The word extension in immigration terms means that you seek to continue engaging in the same activity as a scholar for which you originally came to the U.S. (same school, same lab, same department, etc.).
As a scholar your maximum extension time depends on the visa type. The H-1B visa has a total time of 6 years (with an exception for certain pending permanent residence cases). The J-1 visa in the Research Scholar/Professor category has a limit of 5 years. The J-1 Short-Term Scholar category has a maximum time limit of 6 months.
Generally speaking, requesting an extension through the HIO will extend your permission to remain in the U.S. The visa stamp in your passport will not automatically be extended. If you travel outside of the U.S. after the visa stamp in your passport expires, you will need to apply for a renewal of your visa at the U.S. embassy or consulate in your country in order to return to the U.S. in status. It is not possible to renew a visa within the U.S.
For more information about extensions and how to request one for your visa status, please see below.
If J-1 scholars wish to extend their J-1 visa status they must apply before their current Form DS-2019 expires (see the dates on section #3 of the DS-2019 form). Extensions are not always possible. The extension requested must be within the limitations of the J visa category. There must be adequate funding to cover the new time period, and the department must support extending the academic appointment with the University.
The HIO sponsors several different categories of J visas and each has different eligibility criteria for extending time in the US. The category type is listed on the DS-2019 in section #4. Professors and Research Scholars are eligible for aggregate of 5 years. The Short Term Scholar has a maximum of 6 months. Once a scholar has confirmed that he/she is eligible for an extension and the Harvard reappointment and funding has been finalized, then the HIO may issue an extended Form DS-2019. The request should come from the Harvard or affiliate department to the advisor in the HIO. The HIO also issues departments a memo months prior to the expiration of the Form DS-2019 asking if an extension will be requested. Departments complete the extension form and return it to the HIO, or contact the HIO advisor directly to request an extension.
The H-1B extension process is identical in paperwork requirements as it is for an initial H-1B application. An H-1B extension petition will require a new prevailing wage and a new labor condition application (LCA) along with new supporting documents. A petition must be filed before the current H-1B status ends in order to allow an individual to maintain status and continue to remain on payroll.
The earliest an extension can be filed with USCIS is 6 months prior to the end date of the current H-1B status. If a petition is filed in a timely manner, an individual in H-1B status is authorized to continue to work and be paid for up to 240 days after the expiration of his/her current H-1B status. The HIO will fax a letter to the appointing department once the extension petition has been filed with USCIS to verify an individual's eligibility for continuing work authorization.
Once the extension petition is approved by USCIS, individuals traveling abroad may need to visit a U.S. embassy or consulate to get a new H-1B visa stamp before returning to the United States. Canadian citizens do not need to obtain H-1B visas in their passports.
Extensions of O-1 status are available in one year increments. The O-1 extension process requires submission of proof that the employment is ongoing and generally includes updated evidence of extraordinary ability. A petition must be filed before the current O-1 status ends in order to allow an individual to maintain status and remain on payroll.
If a petition is filed in a timely manner, an individual in O-1 status is authorized to continue to work and be paid for up to 240 days after the expiration of the current O-1 status. The HIO will fax a letter to the appointing department once the extension petition has been filed with USCIS to verify an individual's eligibility for continuing work authorization.
Once the extension petition is approved by USCIS, individuals traveling abroad may need to visit a U.S. Embassy or Consulate to get a new O-1 visa before returning to the United States.
Individuals are admitted in TN visa status in three-year increments initially, but the TN status may be renewed indefinitely. The more expeditious way to extend TN visa status or to move to a different employer in TN status is to travel outside the United States and obtain the TN visa status by reentry. The process is identical to that of the original TN application. The longer way to extend TN status is to have the HIO file for an extension application with a USCIS center. It could take up to four months for the process. Although there is no fixed time limit on the TN visa, individuals are required to have a residence abroad which they have no intention of abandoning.