The National Agricultural Library is one of the world's largest and most accessible agricultural research libraries. It serves as a National Library of the United States and as the library of the United States Department of Agriculture.

The National Agricultural Library was created as the departmental library for the U.S. Department of Agriculture in 1862 and became a national library in 1962. One of four national libraries of the United States (along with the Library of Congress, the National Library of Medicine, and the National Library of Education ), it is also the coordinator for a national network of state land-grant and U.S. Department of Agriculture (USDA) field libraries. In its international role, the National Agricultural Library serves as the U.S. center for the international agricultural information system, coordinating and sharing resources and enhancing global access to agricultural data. The National Agricultural Library's collection of over 3.3 million items and its leadership role in information services and technology applications combine to make it the foremost agricultural library in the world.

The library operates the Agricola database of scientific literature.