The Chamber of Commerce of the United States has matured into the largest lobbying group in Washington. Formed in April of 1912 at the request of President William Howard Taft (1857-1930), the Chamber's commitment to be the voice of business is well documented. The records contain articles of incorporation, bylaws, resolutions and minutes of annual meetings. Presentations to Congress, speeches by members, and conferences hosted by the Chamber. Numerous publications give insight into the concerns facing American businesses in the twentieth and twenty-first centuries.

The Phoenix Steel Company began in the late 18th century as a manufacturer of cut nails. It later became a major producer of railroad rails and iron and steel structural members. Claymont Division of the Phoenix Steel Corporation was established in 1960 when the company purchased the Claymont, Delaware steel plant from the Colorado Fuel and Iron Company. This small collection of materials originating from the Claymont steel plant includes miscellaneous plant announcements, catalogs, labor agreements, photographs, company-issued newsletters, and brief historical essays on the Phoenix Steel Corporation and its predecessors.