Let's say you came for a vacation or tourist visit to the United States using the Visa Waiver Program (VWP), but ended up staying just a little longer then the 90 days authorized on the I-94 Arrival/Departure Record that Customs and Border Protection (CBP) prepared for you upon entry. You might be rightfully worried you won't be able to come back for another visit.
What will happen? There's good news and bad news.
The bad news: Because you stayed past the date authorized by the Department of Homeland Security, you will be ineligible for the Visa Waiver Program (VWP) and might have a more difficult time obtaining a visa to enter the United States in the future.
In preparing your visitor visa application, you will need to provide plenty of evidence to prove your "nonimmigrant intent" (that you intend to return home when your permitted stay is over) and that you can afford your trip to the U.S., such as an itinerary showing your return date, proof of your permanent job or residence in your home country, and financial documentation. To learn more about this, read Application Process for a B-1 or B-2 Visitor Visa.
You can also expect further questioning at the U.S. border because of this past immigration violation.
The good news? You will not be subject to a time bar on reentering the U.S., so long as your overstay did not last more than 180 days. Make sure that you have proof of your date of departure (passport stamp or plane ticket, for example) in order to prove that your brief overstay shouldn't trigger a time bar. For more information on how spending time in the U.S. without permission creates a lengthy period of inadmissibility, see Consequences of Unlawful Presence in the U.S.–Three- and Ten-Year Time Bars.
People who travel to the U.S. on the VWP have less access to immigration relief than actual visa holders. For instance, there is no way to extend a U.S. visit on the VWP unless you encounter an emergency situation, such as a medical problem, that prevents you from leaving. If that happens, you can ask U.S. Citizenship and Immigration Services to grant a period of satisfactory departure of 30 days or less.
If you qualify based on persecution in your home country, you may also apply for asylum. See Who Can Visit the U.S. on the Visa Waiver Program (VWP) to learn more about your rights and obligations while on the VWP.