United States National Agricultural Library

The United States National Agricultural Library (NAL) is one of the world's largest agricultural research libraries, and serves as a national library of the United States and as the library of the United States Department of Agriculture. Located in Beltsville, Maryland, it is 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).

More information on the Wikipedia page.

The website is.