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LC Classification: Home

A breakdown of the Library of Congress Classification system


Murphy Library uses the Library of Congress classification system to organize its materials.

The charts included in this LibGuide are not exhaustive, but are intended to cover the general areas of knowledge.


The classification was invented by Herbert Putnam in 1897, just before he assumed the librarianship of Congress.

With advice from Charles Ammi Cutter, it was influenced by his Cutter Expansive Classification (developed in the 1880s) and by the DDC, Dewey (from 1876). It was designed specifically for the purposes and collection of the Library of Congress to replace the fixed location system developed by Thomas Jefferson.

By the time Putnam departed from his post in 1939, all the classes except K (Law) and parts of B (Philosophy and Religion) were well developed.


  • Class A - General Works
  • Class B - Philosophy, Psychology, Religion 
  • Class C - Auxiliary Sciences of History (General) 
  • Class D - World History (except American History) 
  • Class E - American History 
  • Class F - Local History of the United States and British, Dutch, French, & Latin America 
  • Class G - Geography, Anthropology, Recreation 
  • Class H - Social Sciences 
  • Class J - Political Science 
  • Class K - Law
  • Class L - Education 
  • Class M - Music 
  • Class N - Fine Arts 
  • Class P - Language and Literature 
  • Class Q - Science 
  • Class R - Medicine 
  • Class S - Agriculture 
  • Class T - Technology 
  • Class U - Military Science 
  • Class V - Naval Science 
  • Class Z - Bibliography, Library Science

For more detailed information, visit the Library of Congress Classification Outline.

Research Assistance

Reference Desk

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