After World War I started, all non-naturalized "Enemy Aliens" were required to register with United States authorities as a security measure.
Registrants were from all walks of life. For the State of Kansas the registered aliens represent a broad cross-section of the German-born population of the State.
NARA has a database of this set of records, but it is not indexed, and is tricky to search. I spent time creating indexes for the registrants (over 6,000 names!)and putting them in alphabetical order.
For 120 of the 6,000 registrants there are online digitized images of their registration papers at NARA. This contain details such as year of immigration plus ship name and port of arrival, maiden names of wives, parents' names (including mother's maiden name), place and date of birth, childrens'names and birth dates, siblings names and places of residence, photo,fingerprints, and more.
Those names without online digital images have more details such as place and date of birth, residence, etc. The full records can be obtained offline for these registrants.
The index I have created is for almost 6,000 affidavits filed in the Kansas Judicial District, 1917-1921.
This index is online and searchable at
You can also start at
and follow the link on that page.
I have written out detailed instructions on how to use the online index to find the full records on NARA's online database, and how to order the records for those names without online images.
Enjoy, and I hope you find an ancestor or two :-)