District of Columbia Naturalization and Citizenship
Naturalization records have been filed in the county and district courts of the District of Columbia. Early circuit court naturalizations have been published in the National Genealogical Society Quarterly, Volumes 41-45 (Book FHL 973 B2ng; Film FHL 001289 has Volumes 42-43]).
The National Archives has district court naturalization records from 1802 to 1906. Most of the documents are declarations of intention or orders of admission. They are indexed to 1909. You can write to the National Archives for further information. The Family History Library has not acquired naturalization records for the District of Columbia.
Citizenship and Immigration Services
For naturalization records after September 1906, you may use the Genealogy Program of the Citizenship and Immigration Services or CIS.