United States lawful permanent residency is the immigration status of a person authorized to live and work in the United States of America permanently.
A United States Permanent Resident Card (USCIS Form I-551), formerly Alien Registration Card or Alien Registration Receipt Card (INS Form I-151), is an identification card attesting to the permanent resident status of an alien in the United States. It is known informally as a green card because it was green from 1946 until 1964, and it reverted to that color on May 11, 2010. Green card also refers to an immigration process of becoming a permanent resident. The green card serves as proof that its holder, a lawful permanent resident (LPR), has been officially granted immigration benefits, which include permission to reside and take employment in the United States. The holder must maintain permanent resident status, and can be removed from the United States if certain conditions of this status are not met.