How to Find Chicago Naturalization Records

Cook Count naturalization records are available from 1871 forward. (Earlier records were destroyed by the Chicago Fire.) They were created by five courts: Criminal, Circuit, Superior, County, and District. Records from the first four are held by the Cook County Circuit Court Archives. Records from the District Court are held by the National Archives at Chicago.

The earliest Cook County naturalization records provide little, if any, genealogical information. However, if the declaration was filed in another location, the file might include helpful details.

Records from 1904-late 1906 can include birth date and town, departure and arrival information, and occupation.

Records from October 1906 forward generally include birth dates and places for the applicant's wife and children and a physical description of the applicant. For more information, please see the Cook County Circuit Court Archives' Important Information about Naturalization Searches page.

The first step in finding a Cook Cook County naturalization record is to search an index.

Start by searching Illinois, Northern District Naturalization Index, 1840-1950 at FamilySearch.

If you don't find a match that way, you can also browse the cards at the same site but first you will need to obtain the soundex code for the surname you're searching. Try the Rootsweb Soundex Converter. Once you've selected the correct group of records, play the high-low number game to focus in on the given name you're looking for. (The cards are alphabetical by given name within each Soundex code.)

Another option is to search the same Soundex cards at using their All U.S. Naturalization Record Indexes, 1791-1992 (Indexed in World Archives Project) database. It's searchable by name, birth year, immigration year, and state of residence.

If you prefer microfilm and live in the Chicago area, you can find the Soundex index at the Circuit Court Archives and at IRAD at NEIU. It can also be accessed on Family History Library microfilm. Indexes specific to the four county courts are also available on microfilm and these indexes (not the Soundex) are available at the Wilmette Family History Center.

You can also browse images in the Illinois, Northern District (Eastern Division), Naturalization Index, 1926-1979.

Naturalization records for the Circuit, Criminal, County, and Superior Courts, 1871-1929, can be obtained at the Circuit Court Archives.

If you're not able to visit to obtain the records in person, Kim can provide digital images of naturalizations held by the Circuit Court Archives. Please see my Naturalization, Cook County, (Circuit, Criminal, Superior, and County Courts Only) on for details.

Some District Court naturalization records are available online for free at FamilySearch in a database titled Illinois, Northern District Petitions for Naturalization, 1906-1991. Use the petition number from the Soundex index to find the correct image.

District Court naturalization records that aren't online there can be ordered online at the National Archives at Chicago web page or they can often be obtained by one of Genlighten's Salt Lake City providers.

Many Cook County naturalization records can also be found on FamilySearch films. Search for Author Number 403949 to bring up a list of the available District Court records. Search for "Illinois, Cook" and select "Naturalization and Citizenship" to bring up a list of the other court naturalization records available on microfilm. "


What information is on the records?

The Circuit Court information sheet titled Cook County Naturalization Records provides an excellent summary of how to search for naturalization records in Cook County. Also see the Circuit Court Archives' Important Information about Naturalization Records to learn what information you'd expect to find on documents from various years.

Which courts handled naturalization?

Up through 1929, Cook County naturalization could take place in one of five courts: Circuit Court, Superior Court, County Court, Criminal Court or the United States District Court. After 1929, all naturalization was done through the District Court.

If you are researching an individual who naturalized before the 1890s, the Chicago Voter Registration Lists for 1888, 1890, and/or 1892 (available on may list the court.

Are naturalization records available through Family History Centers?

Yes. Follw these links to view the Family History Library Catalog entries for Cook County naturalization records:

Criminal, County, Circuit and Superior Court Naturalization Records

District Court Naturalization Records