I'm a lawful permanent resident who has been living in Mexico and working in the U.S., and have a green card with a commuter notation. Sometimes I stay in the U.S. for weeks at a time. Am I working my way toward eligibility for U.S. citizenship? When can I apply for naturalization?"
If you are a commuter green card holder (either a daily or seasonal commuter), you are not eligible for naturalization because you are living outside the United States and therefore cannot meet the continuous residency requirement. In other words, as a commuter, you are not working your way toward eligibility for U.S. citizenship.
You will be able to apply for naturalization if you move and take up residence in the United States and your residency continues for the required statutory period. For information on the residency requirement see our article “When Can I Apply for U.S. Citizenship?”
When you enter the United States with the intention of setting up residence permanently, you should inform the officers at the border and file Form I-90 soon after your entry so that you can obtain a new permanent resident card that does not indicate you are a commuter.
There's another section of the immigration rules you should know about as a commuter to the United States. If you stop working in the U.S. for a continuous period of six or more months, you may lose your permanent resident status altogether.
This rule applies even if you enter the United States for reasons other than work during that six- month period. There are exceptions that apply (1) to people whose unemployment is due to circumstances beyond their control (other than lack of job opportunities; for example, illness or injury) and (2) to people who can prove to border officials that they have worked in the U.S. for a total of 90 days in the 12-month period before the date of their application for admission to the United States. See 8 C.F.R. §211.5.
Immigration officials generally require that commuter green card holders, every six months, complete Form I-178 and provide proof of regular and stable U.S. employment and proof of residency in either Canada or Mexico. Therefore, if you believe that you will be out of regular and stable employment, you should consider moving back to the United States in order to preserve your lawful permanent resident status.