Permanent resident aliens are given the legal right to live in the United States forever. The U.S. Citizenship and Immigration Service indicates they are “commonly referred to as immigrants.” USCIS usually issues such residents form I-551, better known as a green card.
According to the Internal Revenue Service, permanent resident aliens maintain their citizenship status unless they voluntarily give it up in writing to the USCIS. They can also lose their status by administrative order of the USCIS or by judicial order of a U.S. federal court. These residents are subject to the same tax laws as U.S. citizens, and they are allowed to apply for full U.S. citizenship after five years as a permanent alien resident.