Utah Naturalization Records, 1906-1930
US District Court (Utah)
Petitions for naturalization and petition evidence, 1912 Feb-1914 Mar, vol 3, no 151-249
The watershed year for naturalization in the United States is 1906. Before that date, anyone (with a few restrictions) could apply for citizenship in a local state court. After that date the U.S. Federal District Courts assumed all naturalization actions. If your ancestors arrived in America after the Revolutionary War, there is always the possibility that they applied for citizenship. It is a good idea to have a basic understanding of the process and the documents that may have been created. Many researchers become aware of the potential for naturalization documents when they see a "NA" notation on a U.S. Census record.
The Unites States National Archives has many of the records subsequent to 1906. Many of these records have been digitized and are also available online. The FamilySearch.org Historical Record Collections have free access to 53 collections of naturalization records. There are additional naturalization records on Ancestry.com, Here is a list of other websites that may contain other records, see "Online Searchable Naturalization Records and Indexes."
The U.S. National Archives explains:
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 percent had not become naturalized or filed their "first papers."From 1890 to the present, the laws concerning naturalization have become more and more complicated. A list of the major naturalization laws can be found in the FamilySearch.org Research Wiki article, "United States Naturalization Laws." The Research Wiki also contains a very good summary of the entire process of naturalization. See "United States Naturalization and Citizenship."