How much information is found on them will depend on when the naturalization was done. The naturalization process did not have to happen in one court, or in one state. It was not mandatory and not all aliens became citizens, and not all completed the process once they started it.

Naturalization is the process by which an alien becomes an American citizen. It is a voluntary act. Naturalization is not required. Of the foreign-born persons listed on the 1890 through 1930 censuses, 25 % had not become naturalized or filed their first papers.

In general, after living in the United States for 2 years, an alien could file a Declaration of Intent (also called First Papers) to become a citizen. After 2 additional years, the alien could Petition for Naturalization. After the petition was granted, a Certificate of Citizenship was issued to the alien. See Changes in Requirements for specific time periods from 1790 to present.

Before 1906, the declaration of intent generally contains more genealogically useful information than the petition. Petitions before 1906 usually show only a name, former allegiance, and date of naturalization. The declaration may include the alien's exact date of immigration into the United States.

After 1906 the opposite is true. The declaration contains preliminary information and may have incorrect dates of arrival and anglicized names. However petitions after 1906 have information that has been verified and matched to an immigration record. An immigrant who arrived after June 29, 1906, could not naturalize until the government located their immigration record (a passenger list).

Since 1906, after an immigrant filed a Declaration of Intention or a Petition for Naturalization in a naturalization court, the Bureau of Naturalization was called upon to provide a certification of the immigrant's arrival record.

The certification, called a Certificate of Arrival was sent to the courthouse. This was done to satisfy the naturalization requirement that everyone who arrived since June 29, 1906 had to have a legal immigration record if they wanted to become a U.S. citizen.

To learn how to find a World War I soldier naturalization, read the rest of "Naturalization of Members of the US Armed Forces During World War I"

Note that all naturalizations prior to Sept. 27, 1906, are termed Old Law (OL). Any replacement had to be issued by BCIS on an OL certificate (There will be an OL number at top right). These C-Files have genealogy valule because many pre-1906 court naturalization records contain little or no information. The application for the OL replacement contains information often unavailable elsewhere. Only BCIS has the OL series of C-Files containing the applications for replacement. It is important to note that OL certificate files exist ONLY when the following three conditions occured:

• the person was naturalized before 1906 AND
• they lost their original certificate AND
• they applied for and got a replacement AFTER 1906.

Declarations filed after Sept 27, 1906, were only good for 7 years. If the immigrant did not petition within the 7 years, the declaration expired and the immigrant had to start over again from the beginning.

Most C-Files from 1906 to 1956 are on microfilm, with the remainder in paper form, and BCIS has an index to those that have been filmed. They are available with a Freedom of Information/Privacy Act request to BCIS Headquarters in Washington, D.C. For naturalization records after 1956, Freedom of Information requests must be sent to the appropriate BCIS District Office

• Wives: Derivative citizenship was granted to wives of naturalized men. From 1790 to 1922, wives of naturalized men automatically became citizens. This also meant that an alien woman who married a U.S. citizen automatically became a citizen. Between 1907 and 1922 an American woman who married an alien lost her American citizenship, even if she never left the United States.
• Minor Children:Derivative citizenship was granted to minor children of naturalized men. From 1790 to 1940, children under the age of 21 automatically became naturalized citizens upon the naturalization of their father. Minor children could also derive US citizenship if their mother married aa American citizen.
• Aliens: From 1824 to 1906, minor aliens who had arrived in the United States as a minor at least 3 years before their 18th birthday could petition for naturalization at the age of 21.
• Military: An 1862 law allowed honorably discharged Army veterans of any war to petition for naturalization, without having filed a declaration of intent, after only 1 year of residence in the United States. An 1894 law extended the same privilege to honorably discharged 5-year veterans of the Navy or Marine Corps. Over 192,000 aliens were naturalized between May 9, 1918, and June 30, 1919, under an act of May 9, 1918. Laws enacted in 1919, 1926, 1940, and 1952 continued preferential treatment provisions for veterans.