History and Genealogy
Certificate Files, September 27, 1906 - March 31, 1956
Certificate Files, or "C-Files," document naturalizations - the acquisition of United States citizenship after birth. C-Files contain copies of records evidencing the:
C-Files are a product of the Basic Naturalization Act of 1906. That law created the Federal Naturalization Service and required the new agency to collect and maintain copies of all naturalization records nationwide. The C-File series later expanded to include records of U.S. citizenship acquired by derivation (naturalization by virtue of qualifying relation to another who is a birthright or naturalized citizen) and resumption or repatriation by former citizens that expatriated themselves (lost their U.S. citizenship).
Between September 27, 1906 until March 31, 1956, the Federal Naturalization Service stored its citizenship records in C-Files. Certain C-File documents are duplicated in the records of naturalization courts across the nation. Other C-File documents are unique.
The United States adopted judicial naturalization in 1790 and the nation's courts conducted most naturalization proceedings until the late 20th century. For most of American history, an immigrant seeking naturalization almost always petitioned a court. A judge decided the applicant's eligibility for citizenship and entered an order either granting or denying the petition. The clerk of the court then made a permanent record of the proceedings in the court's records.
Before the Basic Naturalization Act of 1906, the United States lacked a central repository for naturalization records. Each naturalization court could issue its own version of naturalization certificate and only the naturalization court itself retained a copy of an immigrant's naturalization records.
The Basic Naturalization Act of 1906 required naturalization courts to begin using standard naturalization forms for the first time and the new Federal Naturalization Bureau to keep duplicate copies of all court naturalization records beginning on September 27, 1906. Thereafter, courts forwarded copies of Declarations of Intention, Petitions for Naturalization, and Certificates of Naturalization to Washington, D.C. The Naturalization Service filed the copies of court naturalization records from across the country in its C-Files.
Subsequent naturalization acts expanded the Naturalization Service’s authority and allowed the creation of additional C-Files relating to derivative citizenship, resumed U.S. citizenship, and repatriation. The Bureau of Naturalization’s various programs ultimately resulted in ten unique sub-series of C- Files. Each of the ten C-Files sub-series is distinguished by the method of obtaining U.S. citizenship or the legislation under which an immigrant’s citizenship was granted:
Derivative Citizens – Persons automatically acquiring U.S. citizenship by virtue of their relationship to an American citizen:
Repatriated Citizens – Persons readmitted to U.S. citizenship after relinquishing their citizenship by some voluntary action:
For more information about the 10 C-Files Series, see the Certificate Series table.
USCIS is the current custodian of the C-Files. USCIS' predecessor, the Immigration and Naturalization Service (INS), microfilmed C-Files dated 1906 to ca. 1944 (C-1 to C-6500000) in the 1950’s. Sadly, the original files were destroyed. The only C-files below C-6499999 remaining in paper form are those that were:
Immigrants with C-Files below C-6500000 may have additional USCIS files depending on their arrival date or naturalization date. Some C-Files below C-6500000 are “Consolidated C-Files.” Consolidated C-Files are the only file on an individual subject and contain all agency records pertaining to that immigrant. Consolidated C-Files are only available in hard copy.
C-Files contain copies of records relating to all:
Biographical Content of Forms –The standardized naturalization forms introduced by the Federal Naturalization Act in 1906 called for the immigrant’s name, date and place of birth, and port and date of arrival. Declarations of Intention and Naturalization Certificates issued after July 1, 1929, also include a picture of the petitioner.
Reliability – Confirmation of naturalization applicants' information by the courts and Naturalization Service Examiners made C-Files reliable records. When applicants claimed arrival after June 30, 1906, the Naturalization Service verified the arrival information by checking the original immigration arrival record. For more information about immigration arrival records, which are now preserved by the National Archives and Records Administration (NARA), see NARA's immigration research page.
Naturalization Records Duplicated in Court Records – Original records of judicial naturalization are court records, including Declarations of Intention and Petitions for Naturalization. Some courts also retained Certificates of Arrival (evidencing lawful admission to permanent residence) issued by the Immigration Service among their records.
Between September 27, 1906, and the early 1990’s, naturalization courts maintained original judicial naturalization documents and sent duplicate copies to Washington D.C. to be filed with the U.S. Naturalization Service. Accordingly, most but not all, naturalization records can be found among court records.
Naturalization Records Not Duplicated in Court Records – Despite the standardization mandated by the 1906 naturalization law, different C-Files may contain different forms and not all C-File documents will be duplicated in court records (i.e., these records are only available from USCIS). When an immigrant naturalized, the provisions of law under which s/he applied for citizenship, and whether there was any further activity in his or her case after naturalization could all affect the records contained in his or her C-File. The different types of naturalization records in an immigrant’s C-File may provide valuable clues into the events of his or her life:
Index Search Issues – The most frequent complication encountered when searching for C-Files is identifying the correct naturalized citizen when many other immigrants have the same or similar names and dates of birth. If multiple index references match the requested immigrant, reference to the actual records can help locate the right file. Whenever available, please include the following biographical information with your Index Search Request. Any of these facts could distinguish your immigrant:
Record Request Issues – Unless you are certain of your immigrant's C-File number, you are strongly encouraged to submit an Index Search Request before your Records Request. Besides avoiding a wrong number, the Index Search may also identify additional immigration records that you may want to include in your Records Request.
For more information about where to find C-File Numbers, see Where to Find a C-File Number.
Last Reviewed/Updated: 09/17/2013