REFERENCE WORKS: Generally, the category of works we call "reference" includes atlases, almanacs, bibliographies, dictionaries, directories, encyclopedias, guidebooks, handbooks, indexes, manuals, yearbooks—materials we "refer" to rather than read entirely. Go to these for definitions, topic overviews or background information. Reference librarians can help you find these.
Gale Encyclopedia of Multicultural America, 3rd ed. by
This latest edition includes ethnoreligious groups such as Jews, Chaldeans, and Amish, 23 new ethnic groups, and 152 revised ethnic entries. Approximately one-third of the essays will include a recipe for a traditional dish associated with the featured group. Maps showing either historical or current population patterns in the United States for each group will accompany essays.
American Immigration by
This is the definitive reference on American immigration from both historic and contemporary perspectives. It traces the scope and sweep of U.S. immigration from the earliest settlements to the present, providing a comprehensive, multidisciplinary approach to all aspects of this subject.
We the People: An Atlas of America's Ethnic Diversity. by
A wonderful resource! As a reviewer wrote: "This book contains a masterful rendition of immigrants' entry and migration within the United States over the 19th and 20th Centuries. Genealogy research is greatly enriched for those researchers seeking the locations and movements of immigrated Americans of many ethnic and national origins. Each subgroup is presented with supporting facts, maps, demographics and concise historical context." Good historical source.
Harvard Encyclopedia of American Ethnic Groups by
From Acadians to Zoroastrians-Asians, American Indians, East Indians, West Indians, Europeans, Latin Americans, Afro-Americans, and Mexican Americans--the Harvard Encyclopedia of American Ethnic Groups provides the first comprehensive and systematic review of the many peoples of this country. It is a guide to the history, culture, and distinctive characteristics of the more than 100 ethnic groups who live in the United States. Each ethnic group is described in detail. Not only the immigrants and refugees who came voluntarily but also those already in the New World when the first Europeans arrived, those whose ancestors came involuntarily as slaves, and those who became part of the American population as a result of conquest or purchase and subsequent annexation figure in these pages. One hundred and twenty American and European contributors have been involved in this effort, writing either on individual groups or on broad themes relating to many. The group entries are at the heart of the book, but it contains, in addition, a series of thematic essays that illuminate the key facets of ethnicity. Several essays probe the complex interplay between assimilation and pluralism--perhaps the central theme in American history--and the complications of race and religion. Numerous cross-references and brief identifications will aid the reader with unfamiliar terms and alternative group names. Appendix II reproduces, in facsimile, hard-to-locate census and immigration materials, beginning with the first published report on the nativities of the population in 1850.
Immigrants in American History by
A chronological study of the migration of various ethnic groups to the United States from 1500 to the present day, this multivolume collection explores dozens of immigrant populations and delves into major topical issues affecting different groups across time periods.
Anti-Immigration in the United States: A Historical Encyclopedia by 
Rediscovering America: the making of Multicultural America, 1900-2000 by
In an accessible timeline format, [this encyclopedia] paints an inclusive picture of our recent past, without sentiment or favor, respecting the true richness and complexity of 100 years in the life of a nation.
Ethnic history is a branch of social history that studies ethnic groups and immigrants. Oscar Handlin (1915-2011) might be considered the father of ethnic history. "He ranks as one of the most prolific and influential American historians of the 20th century, with pioneering works in the fields of immigration history, ethnic history, and social history."
[Oscar Handlin. (2004). In Encyclopedia of World Biography (2nd ed., Vol. 7, pp. 121-122). Detroit: Gale. Retrieved from Gale ebooks]
Early in his nearly half century career as a history professor at Harvard, his most influential work,The Uprooted: The Epic Story of the Great Migrations that Made the American People, won the 1952 Pulitzer Prize in history.
[Kraut, A. M. (2013). Oscar Handlin and "the Idea That We Are a Nation of Immigrants." Journal of American Ethnic History, 32(3), 26-36.]
The Uprooted: The Epic Story of the Great Migrations that Made the American People by
Awarded the 1952 Pulitzer Prize in history, The Uprooted chronicles the common experiences of the millions of European immigrants who came to America in the late nineteenth and early twentieth centuries.