In 1996, Congress passed a law and President Bill Clinton signed it which imposed harsh penalties on immigrants who had accrued unlawful presence. The law went into effect in April of 1997. Unlawful presence is any stay in the U.S. without explicit authorization from the U.S. Citizenship and Immigration Service ("USCIS").
If the alien accrues 180 days, but less than 365 days, of unlawful presence and leaves the U.S. before removal proceedings begin against them, they would have a 3-year bar, prohibiting them from returning for three years. A formal grant of voluntary departure in order to constitute leaving before formal deportation begins.
An alien who leaves the U.S. after receiving a notice to appear (the mechanism by which deportation starts), is not subject to the 3-year bar according to the statutory language. However, the alien must leave before he or she has accrued more than one year of unlawful presence, thereby triggering the 10-year bar.
The 10-year bar applies to any alien who accrues more than one year of unlawful presence and leaves the U.S. Such an alien would be barred from returning to the U.S. for ten years from the date of departure.
Unlawful presence must accrue during a single stay. The length of the alien's unlawful presence is not calculated by including multiple unlawful stays in the U.S.
It is important to remember that the bar is triggered by departing the U.S. This is true even if the alien has been authorized to travel through advance parole or a refugee travel document. It is also important to keep in mind that some bars may be overcome with a waiver.
Waivers and bars are a complicated area of federal immigration law. If you find yourself in a situation where you or a loved one have accrued unlawful presence, you probably want to speak to an experienced immigration attorney to discuss your case.