The U.S. Department of Labor Library, established in 1917, is one of the oldest Cabinet-level libraries. The Library was created with the consolidation of the libraries of the former Children's Bureau and the Bureau of Labor Statistics. Large segments of the Library’s collection, which document the history of labor, labor unions and the growth and development of the labor movement in a national and world context, are unique either in their nature and content or in the length and completeness of their coverage. The Library's role as an information repository and access point is central in supporting the day-to-day regulating, monitoring, and analytical work of the Department.

The Library's online catalog provides access to all materials that have been acquired by the Library since 1975, as well as access to selected pre-1975 items. All catalog records, however, have not been converted to electronic format and a card catalog still provides access to most holdings acquired prior to 1975.

The Library's journal collection, which is predominantly historic, is distinguished by a large collection of labor union newspapers and periodicals, numbering more than 3,000 titles. Labor union newspapers representing more than 60 national unions, some no longer in existence, date to the 1860s. More than 400 American trade unions are represented by their constitutions, proceedings, reports and journals. Foreign union publications are extensively represented as well.

On March 28, 2000, the Library was dedicated in honor of former U.S. Secretary of Labor Willard Wirtz and his wife Mrs. Jane Wirtz to become the Wirtz Labor Library of the U.S. Department of Labor. In the same year, the Library was designated a Millennium Library by the White House Millennium Council in recognition of its unique historical holdings.