Skip to Main Content

Library of Congress Classification

Resources

Resources on this topic

Below are some materials from our catalog that explore the Library of Congress classification system. 

How to Read a Call Number

Library of Congress (LC) Call Numbers are like an item's address to help you find where it lives on the shelf. Each letter stands for an academic discipline. In the image below, is for Education, LD is for Individual Institutions - United States. Can you guess which institution is at LD781.M47 H47 2009?

Photo of UC Merced Library shelves with books displaying call numbers in the LD781 range.

A magnified image of call numbers in the LD781 range.

To read a call number, read the number from left to right or top to bottom as follows:

  1. Alphabetically (L before LC, LC before LD)
  2. Numerically (781 before 782)
  3. Alphabetically (.M before .N
  4. Decimal order (.M47 before .M48 or .M5
  5. (Sometimes there are more pieces in alphabetical and then numerical order here, e.g.: H47)
  6. Finally, chronologically (2009 before 2010) This is year of publication and may or may not be included.

Lastly, the shelf is organized from top to bottom in sections, so you'll zig-zag down each section A zig zagging arrow starting at top left and moving across to the right, then down and back to the left and moving across to the rightto look for your call number before moving to the next section of the shelves.

Index finger pointed rightTIP! There are maps of the "stacks" (library shelves) at the end of each aisle.