Immigrants began to settle in Iowa around 1833. The Family History Library has many books about the different ethnic groups that settled in Iowa, including Amish, Danish, Dutch, German, and Swedish immigrants. These books may contain biographical information about individuals, groups that immigrated together, and ministers who immigrated with members of their church congregation.
An excellent bibliography about the different immigrant groups is:
- Ancestry’s Red Book: American State, County, and Town Sources  Contains bibliographies and background information on history and ethnic groups. Also contains maps and tables showing when each county was create
- Iowa History Reference Guide 
- Iowa History and Culture: A Bibliography of Materials Published Between 1952 and 1986. (Cited fully in the "For Further Reading" section of this article.)
There were relatively few African Americans in Iowa before the Civil War. For a list of books and articles about slavery in early Iowa, see pages 5–6 of:
- Iowa in the Civil War: A Reference Guide. 
For books about ethnic groups, see the Locality Search of the Family History Library Catalog under:
- IOWA - MINORITIES
- IOWA, [COUNTY], [TOWN]- MINORITIES
- Eichholz, Alice, ed. Ancestry’s Red Book: American State, County, and Town Sources. Rev. ed. Salt Lake City: Ancestry, 1992. (FHL book 973 D27rb 1992; computer number 594021.)
- Petersen, William John. Iowa History Reference Guide.
- Dawson, Patricia and David Hudson. Iowa History and Culture: A Bibliography of Materials Published Between 1952 and 1986.
- Iowa City, Iowa: The State Historical Society of Iowa, 197- Robertson , James J. Jr. Iowa in the Civil War: A Reference Guide. Iowa City, Iowa: The State Historical Society of Iowa, 197- (Family History Library book 977.7 A1 no. 40; fiche 6049713)