A Green Card holder is an individual who has gained permanent residency in the United States. Such a holder is entitled to dwell within the United States for an indefinite time. Though they are naturalized or a citizen of the United States, they are eligible to live and work within the United States for as long as they wish to stay. Green Card holders are not eligible for the rights of citizenship such as voting or holding office as that is reserved for citizens of the United States. Many Green Card holders will go on to become naturalized but this requires permanent residency within the United States for at least 4-5 years.