Chapter 2 - Becoming a U.S. Citizen
A person may derive or acquire U.S. citizenship at birth. Persons who are born in the United States and subject to the jurisdiction of the United States are citizens at birth. Persons who are born in certain territories of the United States also may be citizens at birth. In general, but subject in some cases to other requirements, including residence requirements as of certain dates, this includes persons born in:
Puerto Rico on or after April 11, 1899; 
Canal Zone or the Republic of Panama on or after February 26, 1904; 
Virgin Islands on or after January 17, 1917; 
Guam born after April 11, 1899;  or
Commonwealth of the Northern Mariana Islands (CNMI) on or after November 4, 1986. 
Persons born in American Samoa and Swains Island are generally considered nationals but not citizens of the United States. 
In addition, persons who are born outside of the United States may be U.S. citizens at birth if one or both parents were U.S. citizens at their time of birth. Persons who are not U.S. citizens at birth may become U.S. citizens through naturalization. Naturalization is the conferring of U.S. citizenship after birth by any means whatsoever.
In general, an applicant files a naturalization application and then USCIS grants citizenship after adjudicating the application. In some cases, a person may be naturalized by operation of law. This is often referred to as deriving citizenship. In either instance, the foreign citizen or national must fulfill all of the requirements established by Congress. In most cases, a person may not be naturalized unless he or she has been lawfully admitted to the United States for permanent residence.
Deciding to become a U.S. citizen is one of the most important decisions an immigrant can make. Naturalized U.S. citizens share equally in the rights and privileges of U.S. citizenship. U.S. citizenship offers immigrants the ability to:
Vote in federal elections;
Travel with a U.S. passport;
Run for elective office where citizenship is required;
Participate on a jury;
Become eligible for federal and certain law enforcement jobs;
Obtain certain state and federal benefits not available to noncitizens;
Obtain citizenship for minor children born abroad; and
Expand and expedite their ability to bring family members to the United States.
2. [^] See INA 303. If the person was born in the Canal Zone, he or she acquired U.S. citizenship at birth if born between February 26, 1904 and October 1, 1979, and one parent was a U.S. citizen at the time of the person’s birth. The Canal Zone ceased to exist on October 1, 1979. See the so-called Torrijos–Carter Treaties (September 7, 1977). If the person was born in the Republic of Panama, but not in the Canal Zone, one parent must have been a U.S. citizen parent employed by the U.S. Government, or by the Panama Railroad Company, at the time of the person’s birth.
5. [^] See Section 303 of the Covenant to Establish a Commonwealth of the Northern Mariana Islands in Political Union with the United States of America, Pub. L. 94-241 (PDF), 90 Stat. 263, 266 (March 24, 1976) (48 U.S.C. 1801 note). In addition, certain persons in the CNMI who were born before November 4, 1986, and their children if under age 18 on that date, became U.S. citizens at that time. See Section 301 of Pub. L. 94-241 (PDF), 90 Stat. 263, 265-66 (March 24, 1976) (48 U.S.C. 1801 note). In addition, the Department of State will issue U.S. passports to persons born in the Northern Mariana Islands between January 9, 1978 and November 3, 1986, pursuant to a judicial decision holding that such persons are U.S. citizens. See Sabangan v. Powell, 375 F. 3d 818 (9th Cir. 2004).
INA 301 - Nationals and citizens of the United States at birth
INA 302 - Persons born in Puerto Rico
INA 303 - Persons born in the Canal Zone or Republic of Panama
INA 306 - Persons living in and born in the Virgin Islands
INA 307 - Persons living in and born in Guam
INA 308 - Nationals but not citizens of the United States at birth
INA 309 - Children born out of wedlock
INA 318 - Prerequisite to naturalization, burden of proof
No appendices available at this time.
Technical Update - Commonwealth of the Northern Mariana IslandsSeptember 30, 2013
This technical update adds the Commonwealth of the Northern Mariana Islands to list of certain territories of the United States where, subject to certain requirements, persons may be U.S. citizens at birth.
POLICY ALERT - Comprehensive Citizenship and Naturalization Policy GuidanceJanuary 07, 2013
USCIS is issuing updated and comprehensive citizenship and naturalization policy guidance in the new USCIS Policy Manual.