How Call Numbers Work

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Books in the California Genealogical Society Library are organized according to the Library of Congress Classification (LCC) system, instead of the more commonly known Dewey Decimal Classification.

LCC is used by academic and special libraries across the United States since the Dewey system is considered suitable only for public and school libraries. The LCC system is criticized as being “U.S.-centric” but it is widely used in this country because of its ease of use and logic.

CGS Librarian Laura Spurrier recently created a hand-out for her talk on the library’s holdings which included a section on “How Call Numbers Work.” She agreed to let me publish it here. I hope you find it as informative and useful as I did.

How Call Numbers Work by Laura Spurrier

The Library of Congress Classification system divides up the universe of knowledge by one or two letters of the alphabet, followed by numbers up to 9999. Complex subjects are subdivided further. Then they are put in order by author (or by title if there’s no identifiable author) and date. For example, Nancy Peterson’s book about San Francisco research, Raking the Ashes, can be found under:

F – Category for local history subjects
869 – California cities
.S3 – San Francisco
P4 – represents Peterson
2006 – year of publication (tells it apart from the next edition)

The F category covers materials about places in the U.S., Canada, the Caribbean and Latin America, including gazetteers, church, cemetery and vital records, periodicals, etc. in each country, arranged by:

Each state (or province) within the region
Counties within that state, in alphabetical order
Cities within that state, (capital city sometimes first)
Miscellaneous, including materials about local minority groups

Other call numbers of interest to genealogists:

BX – histories of religious groups
CS (low numbers) – how-to books and genealogical reference books, The American Genealogist, royal descents, compiled genealogies of multiple families
CS71 – genealogies of individual American families, including family newsletters, in order by surname
CS80-90 – Canadian materials (other Canadian materials are at F1001+)
CS420+ – British nobility and county histories, followed by genealogical materials about other European countries
E99+ – books about Native Americans
E184+ – books about immigrants to the U.S. by ethnicity or religion
E255+ – military and some service pension records (D.A.R. Lineage Books are shelved separately.)
Z – reference books, especially resources in other libraries.
The row ends with the American Genealogical & Biographical Index (Rider) volumes.

Laura J. Spurrier, M.A., M.A., M.L.S., 9/08



  1. Jennifer  October 23, 2008

    Very cool post! I look forward to trying out my new knowledge this Saturday.

  2. Kathryn Doyle  October 31, 2008

    I’m so sorry I didn’t catch you before you left. I was hoping to have a short session with you!