NUCMC via the LOC is Gone. Kaput. Done.
This is a long post. Several of my genealogical education presentations involve locating manuscripts and what those searches yield. Personal papers, business records, records of organizations, diaries, journals, general store ledgers, old address books, Aunt Jenny’s genealogy work from 1920, and many other saved items. I teach how to find these no matter what library, archives, historical society, ethnic organization, or university library special collections might hold things that have clues on our families, places, time periods, wars, and religion. I show the differences in searches done via several free finding aids found online and in repositories. The Historical Records Survey, National Union Catalog of Manuscript Collections (NUCMC), ArchiveGrid, WorldCat, and some others are online. Each search result looks a bit different, and some are very different. The finding aids and search terms on each can offer varying results and the amount of mouse clicks to reach the actual full description varies. This post is an overview mainly to show the demise of one search. Full details on using the finding aids and accessing the results are in my presentation slides and handouts. In this blog post, I am mainly covering NUCMC and on a sad level. I’m not going deeply into the origins of NUCMC and the other finding aids in this post.

In 1959 NUCMC began collecting descriptions of manuscript collections housed in research repositories around the U.S. Over the years, those results have been available in several ways, beginning with annual printed books and evolving into online descriptions. Sure, much of NUCMC can be found on ArchiveGrid and WorldCat today but NOT all of what NUCMC had in the printed and other earlier editions. All are means of finding gems that aid in our research. The latter two are free online as has been NUCMC to a point. I love to show how quick a search could be on NUCMC via its section on the Library of Congress (LOC) website. It also required fewer steps than Worldcat.org to see a full description of a manuscript collection and to determine if it’s something worth further investigation. I do know that Archive Finder (part of ProQuest) states it has all of the NUCMC descriptions back to day one but we can’t use that from home and the repositories that include Archive Finder in their finding aids are not in every library or other repository. Archive Finder also requires an onsite search at repositories and that often limits those who are not members, alumni, students, librarians, etc.
As mentioned earlier, NUCMC began collecting manuscript descriptions from repositories across the U.S. in 1959 and that participation grew and grew. In the 1980s it became an electronic finding aid. In recent years the search on NUCMC on LOC was done via WorldCat. Yet, the results we saw looked very different and required fewer filters to be checked than directly on WorldCat. Via LOC It was usually a quicker search with more immediate results. As I was updating some of my presentation handouts and slides at the end of this past summer, I found that a search using the NUCMC page on the LOC website returned an error code. Tried again with same error. I asked a couple other researchers to check and they also received the error code. Guess what! It’s done. Over. Gone. Out of existence. Useless. Defunct. That search capability is no more and I needed to know what happened.
I finally located a news release from the LOC:
“05/27/2026: The National Union Catalog of Manuscript Collections (NUCMC) was launched in 1959. Over the past 67 years, the program has collaborated with more than 1,800 institutions and repositories, creating bibliographic and name authority access for over 139,000 collections. Through this work, participating institutions and repositories have developed new ways for end users to discover and access their valuable collections. In the past three years, only four institutions have remained active in the NUCMC program for collection access support: America’s Packard Museum (Ohio); the Maine Historical Society; the Swiss Center of North America (Wisconsin); and the University of Montana-Missoula. With the retirement of NUCMC’s last librarian, Roberto Sicre, at the end of May, the Library of Congress will sunset the NUCMC program. The participating institutions have established contingency plans to continue supporting user access to their resources through online finding aids. Questions about the history of the NUCMC program can be sent to [email protected].”
I knew that with so many repositories themselves capable of describing, cataloging, and placing information online about manuscript collections, they no longer contributed to NUCMC. NUCMC on the LOC website began to have a link that said “Searching on OCLC WorldCat” and Searching on ArchiveGrid” instead of simply searching via NUCMC. For several years I have used and liked the search results when clicking on the NUCMC link to WorldCat as opposed to going directly to WorldCat. I use WorldCat, ArchiveGrid, and other finding aids several times each week. I will miss the NUCMC screen version of searching on OCLC WorldCat as it saved me time and produced a full description without extra clicks. (I have some upcoming presentations in which I will demonstrate what EACH finding aid’s results look like and am updating those for upcoming webinars.)
If you wish to learn more about each of these finding aids, check their websites to learn more about their histories, behind the scenes work, and what each includes.
The media release from the LOC is here: https://www.loc.gov/aba/news/



