U.S. Citizens may vote, and if they meet other qualifications, may hold public office. A U.S. citizen may enter, and leave, the U.S. without immigration restrictions, and does not have to undergo immigration enforcement, either in the U.S., or at the border. A U.S. citizen may not be deported from the U.S. Many people are U.S. citizens, even though they don’t know it. There are three ways to become a U.S. citizen: by birth, by derivation, or by naturalization.

There are three ways to become a U.S. citizen: by birth, by derivation, or by naturalization. For a deeper understanding of each, see the questions: Who is a U.S. citizen by birth? How does a person become a U.S. citizen by derivation? How does a person become a U.S. citizen by naturalization?

Under current U.S. law, you are a U.S. citizen by birth if: You were born in the U.S., and you were subject to the jurisdiction of the U.S. at the time of your birth; You were born in the U.S., to a member of an Indian, Eskimo, Aleutian, or other aboriginal (native) tribe; You were born outside the U.S., your parents were married to each other at the time you were born, both of your parents were U.S. citizens, and one of your parents had a residence in the U.S. before you were born; You were born outside the U.S. Your parents were married to each other at the time you were born. One of your parents is a citizen of the U.S. and was physically present in the U.S. for a continuous period of one year before you were born. Your other parent was a national, but not a citizen, of the U.S. You were born in American Samoa or Swains Island, your parents were married to each other at the time you were born, and one of your parents was a citizen of the U.S., and was physically present in the U.S. for a continuous period of one year before you were born. The identity of your parents is unknown, and you were found in the U.S. before you were five years old. (But, if, before you turned 21, it can be shown that you were not born in the U.S., you are not a U.S. citizen.) You were born outside the U.S., and your parents were married to each other at the time you were born. One of your parents was a U.S. citizen, and your other parent was not a U.S. citizen. Your U.S. citizen parent was physically present in the U.S. for a total of five years, and at least two of those years were after your U.S. citizen parent turned 14 years old. If this U.S. citizen parent was outside of the U.S., and was serving in the U.S. Armed Forces, or was employed by the U.S. government or an international organization, or was the dependent child who was living with a person who was serving in the U.S. Armed Forces, or the U.S. government, or an international organization, then your U.S. citizen parent was considered to have been physically present in the U.S. during that time; or You were born outside the U.S., before noon, Eastern Standard Time, May 24, 1934, and your mother was a U.S. citizen, and had resided in the U.S. before you were born. If you were born outside the U.S., and your parents were not married to each other at the time you were born, then you are a citizen by birth if: You were born after December 23, 1952, and your mother was a citizen of the U.S. at the time you were born, and your mother had been physically present in the U.S. for a continuous period of one year before you were born, or You were born between January 23, 1941, and December 24, 1952. One of your parents was a U.S. citizen, and your other parent was not a U.S. citizen. Your U.S. citizen parent was physically present in the U.S. for a total of five years, and at least two of those years were after your U.S. citizen parent turned 14 years old. The identity of your father was established, by law, before you turned 21. If your U.S. citizen parent was outside of the U.S., and was serving in the U.S. Armed Forces, or was employed by the U.S. government or an international organization, or was the dependent child who was living with a person who was serving in the U.S. Armed Forces, or the U.S. government, or an international organization, then your U.S. citizen parent was considered to have been physically present in the U.S. during that time, or Your father was a U.S. citizen at the time you were born, and a blood relationship between you and your father is established by clear and convincing evidence. Also, you must show that your father (unless deceased) has agreed in writing to support you financially until you turned 18, and that one of the following is true: Before you turned 18, your father was declared to be your father by the law of your residence, or Before you turned 18, your father says that he is your father, in writing, under oath, or Before you turned 18, a court has declared that your father is, in fact, your father If you were born outside of the U.S., and your parents were not married to each other, and you claim U.S. citizenship through your father in this manner, you must also be able to show that one of the following is true: You were born outside the U.S., both of your parents were U.S. citizens, and your father had a residence in the U.S. before you were born; You were born outside the U.S. Your father is a citizen of the U.S. and was physically present in the U.S. for a continuous period of one year before you were born. Your mother was a national, but not a citizen, of the U.S.; You were born in American Samoa or Swains Island, and your father was a citizen of the U.S., and was physically present in the U.S. for a continuous period of one year before you were born; or You were born outside the U.S. Your father was a U.S. citizen, and your mother was not a U.S. citizen. Your father was physically present in the U.S. for a total of five years, and at least two of those years were after your father turned 14 years old. If your father was outside of the U.S., and was serving in the U.S. Armed Forces, or was employed by the U.S. government or an international organization, or was the dependent child who was living with a person who was serving in the U.S. Armed Forces, or the U.S. government, or an international organization, then your father was considered to have been physically present in the U.S. during that time. Click here and here to see the law that tells who is a U.S. citizen at birth. NOTE: The laws, that tell who is a citizen of the U.S. at birth, have changed over the years. Several courts have ruled that the law that tells whether you were a citizen at birth, is the law that was in effect at the time you were born. The laws, quoted above, have been in effect since 1994. If you were born before 1994, and are still unsure as to whether you are a citizen by birth, consult an attorney.

A child automatically becomes a citizen by derivation if: The child is not married The child is under the age of eighteen At least one parent of the child is a U.S. citizen The child is a lawful permanent resident of the U.S. (see below about what a lawful permanent resident is) The child is living in the U.S., and is in the legal and physical custody of the U.S. citizen parent.

If you were not born a U.S. citizen, and have not become a citizen by derivation, you may become a U.S. citizen by naturalization. To become a citizen by naturalization, you must: Be a lawful permanent resident; Be at least 18 years of age Have resided in the U.S., as a lawful permanent resident, continuously, for at least five years; (If you have been married to, and living with, a U.S. citizen for three years, and your spouse has been a U.S. citizen for all of those three years, then you only need to show three years of continuous residence as a lawful permanent resident.) For more information on the length of time it takes to become a U.S. citizen, click here. Have been physically present in the U.S., for at least half of the five years, immediately preceding the filing of the application for naturalization; (or for at least half of the three years, if you are married to a U.S. citizen as described above) Demonstrate good moral character; Pass a test showing that you can understand English Pass a test showing that knowledge of U.S. history and government; and Take an oath of allegiance. (To see a heartwarming story about the oath of allegiance, click here. In this article, Judge Denny Chin, who was born in Hong Kong and became a U.S. citizen by derivation at age eleven, writes that one of his most enjoyable duties as a judge was performing the ceremony where citizenship applicants take the oath of allegiance.) NOTE: There are a number of exceptions, that could allow a person to become a citizen, even if he does not meet the above requirements. There are also certain barriers that could prevent a person from becoming a citizen, even if the meets the above requirements. For a more thorough explanation of the naturalization requirements, consult an attorney.

Lawful permanent residents (LPRs) are also known as “green card holders.” Under U.S. immigration law, an LPR has more rights than any other person except a U.S. citizen. An LPR has the right to live permanently in the United States, although an LPR may still be deported under certain circumstances. An LPR may also lose his LPR status if he resides outside the U.S. An LPR may work in the United States. Often, an LPR may travel in and out of the U.S. without advance permission from the government. Also, often, an LPR does not have to go through immigration scrutiny when returning to the U.S. Also, LPRs may become U.S. citizens (see above for naturalization requirements.) The main ways to become an LPR are: Through a family member; Through a petition filed by an employer; Through asylee and refugee status. For an explanation of what asylee and refugee status is, see "How can a person attain the status of Refugee or Asylee?" below. To find out how to become an LPR through asylee and refugee status, click here. Through a pathway available to victims of serious crimes. To see the steps to get a U.S. Green Card, click here.

To be allowed to live in the U.S. as an asylee or refugee, you must prove: You are outside the country of your nationality; Or if you have no nationality, you are outside the country where you last lived; and You are unwilling or unable to return to that country because of persecution, or a well-founded fear of persecution because of your Race Religion Nationality Membership in a particular social group, or Political Opinion. To be granted status as an asylee or refugee, you must send an application to U.S. Citizenship and Immigration Services (USCIS) and have an interview with an asylum officer. After the interview, the asylum officer will decide whether to grant you asylum. If the asylum officer decides not to grant you asylum, you may appeal the officer’s decision. For more information on how to apply for asylum or refugee status, click here. If USCIS grants you asylum or refugee status, you will eventually be able to apply for U.S. citizenship. For more information on how an asylee or refugee may become a citizen, click here.

A nonimmigrant, does not have as many rights as an LPR. Some of the categories below allow a person to work in the U.S.; others do not. Also, many of the categories below do not allow a person to stay in the U.S. permanently. Also, persons in most of these categories, do not have the right to become LPRs; if a nonimmigrant wants to become an LPR, the nonimmigrant must qualify by some other right. The following persons may apply for a “nonimmigrant visa”: Athlete, amateur or professional (competing for prize money only) Au pair (exchange visitor) Australian professional specialty Border Crossing Card: Mexico Business visitor CNMI-only transitional worker Crewmember Diplomat or foreign government official Domestic employee or nanny - must be accompanying a foreign national employer Employee of a designated international organization or NATO Exchange visitor Foreign military personnel stationed in the United States Foreign national with extraordinary ability in Sciences, Arts, Education, Business or Athletics Free Trade Agreement (FTA) Professional: International cultural exchange visitor Intra-company transferee Medical treatment, visitor for Media, journalist NAFTA professional worker: Mexico, Canada Performing athlete, artist, entertainer Physician Professor, scholar, teacher (exchange visitor) Religious worker Specialty occupations in fields requiring highly specialized knowledge Student: academic, vocational Temporary agricultural worker Temporary worker performing other services or labor of a temporary or seasonal nature. Tourism, vacation, pleasure visitor Training in a program not primarily for employment Treaty trader/treaty investor Transiting the United States Victim of Criminal Activity Victim of Human Trafficking Nonimmigrant (V) Visa for Spouse and Children of a Lawful Permanent Resident (LPR) A list of these visa categories, along with more complete explanations, may be found here.

At certain times, the United States Government will allow certain categories of persons to enter, or remain in the U.S., who would not otherwise be allowed to do so. These categories change often. To see if you qualify for any temporary humanitarian category, consult an attorney.

Undocumented persons (often called “illegal aliens”) are non-citizens who are present in the United States, but do not have the legal right to be here. There are two ways that a person can become undocumented: He can enter the country illegally. If he does this, he is undocumented from the moment he enters the country. He can enter the U.S. legally, but can stay longer than he is authorized to stay. If he does this, he is undocumented from the moment that his authorized stay period expires. Under certain circumstances, an undocumented person can change his status and be allowed to remain in the country legally. If you are undocumented, and would like to ask about ways that you may have lawful immigration status, consult an attorney.

The U.S. Constitution says, “The Congress shall have power … To establish a uniform rule of naturalization.” In Hines v. Davidowitz, the U.S. Supreme Court held that, this provision gives Congress the authority to make immigration law. Most of the immigration laws passed by Congress are found in the Immigration and Nationality Act. Also, certain federal agencies have the power to make immigration law. Most of the immigration laws enacted by federal agencies are found in Title 8 of the Code of Federal Regulations. Also, federal courts may make immigration law. Federal courts consist of the U.S. Supreme Court, thirteen courts of appeals, and 94 district courts. Many of these courts have made decisions on immigration law, and these decisions are legally binding. Many of the best websites, for finding federal court cases, charge a fee for access. Two of the best free websites for searching federal case law are Justia and GoogleScholar. These websites provide federal case law on all topics, not just immigration law. Federal court decisions on immigration law are not found in any one place. There are also “administrative courts.” The published decisions of these administrative courts are binding federal law. These courts are part of federal administrative agencies. These are courts not true federal courts, because their judges are not appointed by the President, and their judges do not have lifetime job security, and the judges do not have constitutional protection from having their pay lowered. But, these courts make decisions that are an important part of U.S. immigration law. Many of the immigration law decisions of administrative courts can be found in the “Immigration and Nationality Decisions” available for free here. NOTE: This page only scratches the surface of U.S. immigration law. Immigration Law changes frequently, and, for an update on immigration law, it would be wise to consult an attorney.