This entry was originally written by Patricia Lyn Scott, CA and Gary Topping Ph.D. for Red Book: American State, County, and Town Sources.
In general, naturalization records begin with the date the county was organized, and they may be in one of several courts holding concurrent jurisdiction. Naturalizations that were initiated between statehood (1896) and the federal changes in naturalization process (1906) are easier to locate since the district court was the only court in the state where the process could be started, and each court kept records individually by county in the district court office. Many of these may be found at the Utah State Archives and some are on microfilm at the FHL listed under Utah/[County]/Emigration and Immigration. The Utah State Archives has an excellent online descriptive research guide “Utah Naturalization and Citizenship Records,” at http://archives.utah.gov/referenc/referen.htm. After 1906, in addition to federal courts, an applicant could apply at the state district court for the county or the state supreme court.
Since a large number of Mormons came to Utah from Europe, the number of naturalizations is rather large for a landlocked state. Passenger lists from those Mormon missions in Scandinavia (1872–94) and Europe (1840–1925) are on microfilm at the FHL. Jaussi and Chaston (1974) describe a full collection of emigration records in their book (see Utah Vital Records).