The Fourteenth Amendment to the United States Constitution was adopted on July 9, 1868. Section 1, Clause 1 states that all persons born in the United States are US citizens. This Clause overruled the landmark 1857 United States Supreme Court case of Dred Scott vs. Sandford. The Dred Scott case held that black persons could not be citizens of the United States.
Citizenship due to an individual’s birth in the US results regardless of the tax or immigration status of the individual’s parents. Thus, every individual born within the United States is automatically a US citizen regardless of whether his or her parents were there for a day, a month, as students, on a visit or as illegal immigrants. (There is an exception for children born to foreign diplomats officially serving in the US).
It is also often the case that a person born outside the United States becomes a US citizen at birth. Generally, this happens if at least one parent is a US citizen and has lived in the United States for a certain period of time.
For example, under US Immigration laws, an individual is considered to have acquired US citizenship at birth even if the individual was born overseas and born out of wedlock after December 23, 1952 and his / her mother was a US citizen who was physically present in the United States or its outlying possessions for at least one year of continuous presence prior to the individual’s birth. As another example, an individual born abroad is considered to have acquired US citizenship at birth if one parent is a US citizen at the time of birth, the birth date is on or after November 14, 1986, the parents were married at the time of birth and the US-citizen parent had been physically present in the US or its territories for at least five years prior to the birth, and at least two of those years were after the citizen parent’s 14th birthday. Read more