If you aren’t a US Citizen by birth and you seek and get US Citizenship, US immigration law assumes you are planning to live in the US permanently. Staying outside the US for over a year can result in loss of permanent resident status. However, there are exceptions to this rule.
Exceptions for US Government Personnel
US personnel such as military and civil service employees, together with their children and spouses with lawful resident status, can remain outside America for as long as an official assignment demands. They also enjoy four months after such an assignment has been completed before they risk losing US resident status.
Any other immigrant holding permanent residence status that chooses to reside outside America for over 12 months without seeking approval from the USCIS will be required to get a new visa to gain back entry. A re-entry permit is required. The permit allows the holder to stay outside the US until the re-entry validity period expires. To apply, visit the official USCIS website.
Eligibility After Losing Residence
Suppose you want to reapply for naturalization and do it under INA 316. In that case, you must do five years of continuous residence, then wait for four years after returning to the US to meet requisite continuous residence and apply for naturalization. Statutory deadlines are calculated from the date of filing.
Example on Eligibility for US Citizenship Based on Continuous Residence
Let’s say you apply for naturalization (US Citizenship) under INA 316, leave the US on 1st January 2022 and return on 2nd January 2023, you will have stayed outside America for a year breaking continuous residence. For such a case, you must wait five years (up to 3rd January 2027) to reapply for naturalization.
Although you will have stayed outside the US for less than a year during the statutory timeline, you will still have stayed outside the US for over 6 months, during which a person is eligible for naturalization if you successfully rebut presumption that you have broken continuity of residence.
Some applicants can proactively preserve residence even if they are absent for a year or more to qualify for employment abroad. To do this, you must file Form-N470 application for preserving residence for naturalization.
To qualify, you must be physically present in America as a legal permanent resident for a year before working abroad. You also need to apply before or after your employment begins. However, if you apply after employment begins, it must be before you work abroad continuously for a year.
There are other conditions to consider. For instance, you must be employed or contracted by the US government or American institution, Corporation/American firm in US foreign trade/commerce. A subsidiary of a US firm/Corporation with 50%+ US-owned also applies. Employees of public international companies that the US has a statute/treaty with also meet requirements provided they weren’t employed before becoming legal permanent residents.
If a person is engaged solely on ministerial work of a religious denomination with a bona fide company within America then he/she can preserve residence for naturalization without being subjected to regular conditions.
Summary: How long US citizen can stay outside US?
It depends. While the normal limit is a year, you can stay longer and still preserve your US citizen if you are a military service member, government employee, or meet any other criteria discussed above i.e., work for a US multinational or you proactively preserve residence.