National Agricultural Library (NAL)

From www.goprincegeorgescounty.com:

Established in 1862 under legislation signed by President Lincoln, the National Agricultural Library, along with the Library of Congress and the National Library of Medicine, is one of the three national libraries of the United States. It is the largest agricultural library in the world with over 2.3 million volumes on 48 miles of shelves located on 14 floors.