The congressional material in the U.S. Serial Set includes the committee reports, journals, manuals, and administrative reports of both Chambers in addition to a variety of directories, orations, and special publications (such as illustrated descriptions of the Capitol). Unfortunately, not all these categories appear consistently in the Set.

Committee reports on proposed public and private legislation are among the most important of the U.S. Serial Set's congressional publications and have always been part of the Set. The journals of proceedings of both Houses appeared from 1817 (15th Congress) but have been excluded from the Set since 1953, while Senate and House manuals did not appear in it until 1896, but are still included. The Congressional Directory was privately printed and distributed until 1865, and was not given serial numbering until 1882. Orations and eulogies have always appeared, but recently, addresses on deceased Members of Congress have been printed for distribution outside the U.S. Serial Set scheme.

Administrative reports of the Secretary of the Senate have always been provided with serial numbering, while in the last 30 years the reports of the Clerk of the House of Representatives sometimes have not. The Congressional Record and its predecessors (Annals of Congress, Register of Debates, Congressional Globe) have never been included. Texts of bills and resolutions are included in U.S. Serial Set publications sporadically and on an inconsistent basis.

As a rule, committee hearings and prints have been considered committee rather than congressional publications and have consequently been excluded. Occasionally, however, hearings are printed as or included in U.S. Serial Set publications.

The Senate frequently sat in secret session in early Congresses and proceedings and other records of such sessions (executive journals, executive documents, and executive reports) were not included in the Set except by special order. These types of executive publications should not be confused with executive branch publications that did appear in the U.S. Serial Set with great frequency, especially in the earlier years.