If you hold a green card and have traveled outside the United States during the 5 year (3 years if married to a US citizen) waiting period, and exceeded a length of 6 months outside of the United States, you will not be eligible for naturalization.
Leaving for 6 months or longer is viewed as “abandonment of permanent residence” in the eyes of USCIS. Of course there are circumstances that would be considered by your respective officer should you encounter a situation where you are unable to return within the specified time frame for critical reasons.
The exception to continuous living would be if you are applying under certain types and periods of military service. These exceptions can be found on the USCIS website.
What Do I Do if I Have Left the Country Longer than 6 Months?
A USCIS officer will review your case and reasoning behind leaving the country for longer than the allocated time period. You must show that you had ties to the United States during your time abroad as well.This can include keeping your job in the United States to having immediate family residing in the United States. It is also important to note that a high volume of trips abroad taken are also taken into consideration by your respective officer. All time abroad must strictly not be longer than one year.
If you are abroad for one year and over, USCIS will consider that an abandonment of green card, and you will have to wait four years and one day from the day you entered back into the United States to reapply for citizenship.
Every case is reviewed and approval is contingent upon the respective officer’s decision.