How It Works

In contrast to the DDC, the Library of Congress Classification system (LCC) strives to divide all the world’s knowledge into 21 topical areas and groups them alphanumerically. That is, they first assign a topic area to a letter, and then divide that topic up by numbers. Created by the U.S. Library of Congress to meet the needs of its collection, the first outline of the LCC was released in 1904 (“Library of Congress Classification”).

Library of Congress Classification

A: General Works

B: Philosophy, Psychology, Religion

C: Auxiliary Sciences of History

D: World History

E: History of the Americas

F: History of the Americas

G: Geography, Anthropology, Recreation

H: Social Sciences

J: Political Science

K: Law

L: Education

M: Music

N: Fine Arts

P: Language and Literature

Q: Science

R: Medicine

S: Agriculture

T: Technology

U: Military Science

V: Naval Science

Z: Bibliography, Library Science, Information Resources

The LCC then adds numbers after each letter to get more specific within each topic area. Our example from before has the call number E203.A5725. This call number falls within the range E201–298, which is reserved for works about the American Revolution.

OneSearch item record for a book titled The American Revolution by Charles Carey, showing call number E203.A5725 2004

How to Find a Book on the Shelf

Please watch this video explanation [1:49], which demonstrates the different elements of LCC call numbers and how they are ordered on a library shelf:

Note: This video has open captions. You may also use the text transcript if you prefer to read.


Library of Congress Classification.” Librarianship Studies & Information Technology, 23 June 2020.

Understanding Call Numbers (Research Minutes).” YouTube, uploaded by Ryerson University Library & Archives, 14 Jan. 2011.



Icon for the Creative Commons Attribution 4.0 International License

Introduction to College Research Copyright © by Walter D. Butler; Aloha Sargent; and Kelsey Smith is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.