Thank you for posting your question on History Hub.
To determine if your ancestors ever applied for naturalization, you will want to request a search of their records from the appropriate National Archives location. Naturalization records dated prior to October 1991 from the Federal courts are at the National Archives. The National Archives at Kansas City is the custodian for naturalization records in Iowa. You will need to work directly with staff in that office in order to obtain a copy of the requested record.
In most cases, the National Archives will not have a copy of the certificate of citizenship granted to a petitioner – our holdings normally include only the declaration of intention (with any accompanying certificate of arrival) and petition for naturalization.
Naturalization records from state or local courts are often at state archives or county historical societies.
If the naturalization took place in a Federal court, the declaration of intention (with accompanying certificate of arrival) and petition for naturalization will usually be in the National Archives facility serving the state in which the Federal court is located (https://www.archives.gov/research/court-records).
Normally, the National Archives will not have a copy of the certificate of citizenship.
The naturalization record may contain information on the family members of the individual but should always list their originating country.
If you know which state your ancestor came through when he arrived in the United States, you may also wish to request the passenger lists for the port. The National Archives has immigration and passenger lists records for arrivals to the United States from foreign ports between approximately 1820 and December 1982 (with gaps). The records are arranged by port or airport of arrival. Please consult our website, https://www.archives.gov/research/court-records, for more information on which National Archives location to contact to request a search of the lists.
Records older than 75 years are publicly available, and many have been digitized by National Archives partners including Ancestry.com and FamilySearch.org.
We hope this information is helpful in your research.
The National Archives and Records Administration
Dear Jim White,
Thank you for posting your request on History Hub!
We found some additional information that may help.
Please see this article for general background information:
Searching on Ancestry.com will return a number results for a William Tamlin from the U.K., born between 1829-1832. There are results for William D. Tamlin from Iowa listing his birth as 1832 and there are U.K. census listings prior to the 1850's that list household members, though this does not indicate if this is the W. Tamlin that later emigrated to the U.S.
This material is available online on Ancestry.com. There may be a fee for using Ancestry. Instead, please check for access at your local library as many library systems subscribe to these sites, making them free for their patrons.
We hope this is helpful. Best of luck with your research!