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University Library, University of Illinois at Urbana-Champaign

Library Organization and Classification Systems

This guide will help you understand the different classification systems in the library.

Superintendent of Documents Classification

The U.S. Superintendent of Documents developed this system (also called SuDocs) for the arrangement of federal government publications. Arrangement is generally by issuing agency; for more information see our U.S. SuDoc & Agency List page. Some of the Government Documents collections use this classification system.

SuDocs numbers consist of a letter, designating the particular issuing agency, followed by numbers identifying subordinate bureaus within the agencies and specific publications. Below is a list of prefixes and their corresponding agencies:

  • A: Agriculture Department
  • C: Commerce Department
  • C3: Census Bureau (Commerce Dept.)
  • D: Defense Department
  • E: Energy Department
  • ED: Education Department
  • GA: General Accounting Office
  • HE: Health and Human Services Department
  • I: Interior Department
  • I19: U.S.Geological Survey (Interior Department)
  • J/Ju: Justice and Judiciary
  • L: Labor Department
  • LC: Library of Congress
  • NAS: National Aeronautics and Space Administration
  • S: State Department
  • T: Treasury Department
  • X,Y: Congress