Good Info
As this site is something of a clearinghouse, we are not the only source of information on public domain concerns. It's out there, sometimes definitive, sometimes a bit confused, sometimes designed to sell things to you. (So be aware that there may be financial incentives. You may notice we have nothing to sell and at this point do not even take donations to defray our expenses.) Below are sources of which I am aware that provide good info. If you are aware of others, please drop us a line so that we can add them if we feel it fits.
Be aware there are many sources, mostly not shown below, which provide PD and royalty-free recordings and sheet music. Most, not all, of these sites charge for their service. It's not unreasonable. They can be very useful. We do not promote nor do we denigrate such services; they exist in sort of a parallel universe to our own.
Brown University - "Harris Collection of American Poetry and Plays" has original song sheets of minstrel songs and hymns, large numbers of which were published before 1850. https://library.brown.edu/info/collections/harris/index/
California State at Fresno ( http://www.csufresno.edu/folklore/Contents.html Tons of stuff are found here, way more than we have, with every spelling change, every name variation accounted for. If you are searching for something really, really obscure and it isn't at publicdomainmusic here, they probably have it. Their site is neither quick and Spartan, nor is it fancy. "Comprehensive'" describes it. "Crowded" could also be used. You will also find ample evidence supporting their entries, which I did not attempt. I lack the resources of a university and was not paid for a labor of love. Also, they have information on PD, "Creative Commons", copyright expiration dates, "Fair Use", lists of where to find on-line sound recordings... All-in-all, a tremendous resource. Unfortunately, right now I am getting a lot of "404 Not Found" pages, ones which used to work well.
Citizen DJ (https://citizen-dj.labs.loc.gov/public-domain-2022/) deals with copyright of recordings, which is not the same as copyright of music, but you may wish to know more about it.
Connolly Music "String Ovation" (https://www.connollymusic.com/stringovation/understanding-public-domain-and-where-to-find-public-domain-music) Mentions general info and a few list sources with thousands of titles. It references the PD Info site (below) and the Petrucci Music Library which is generally slanted toward classical pieces.
Duke University Center for the Study of the Public Domain (https://web.law.duke.edu/cspd/): All sorts of stuff here, not specific just to music, however. Celebrates each day when formerly copyrighted works enter the public domain.
Legis Music (https://legismusic.com/background-music-public-domain/) Excellent discussion of the issues involved with copyrighted and non-copyrighted music. It also links to sources of PD and royalty-free music. Note that to use some of these sources, there may be charges, which are related to providing the service, not for the music itself.
Library of Congress "National Jukebox" (https://www.loc.gov/collections/national-jukebox/about-this-collection/) Historic recordings available to use.
Mainly Norfolk (https://www.mainlynorfolk.info/folk/songs/): Long list of English songs, some info, some lyrics.
Mekshq (https://mekshq.com/where-to-find-free-public-domain-music-for-your-video-audio-projects/): Places to find PD and royalty -free music.
New York Public Library (https://www.nypl.org/blog/2019/05/31/us-copyright-history-1923-1964): Good info, but not surprisingly, they focus on books.
Ohio State University Libraries (https://library.osu.edu/site/publicdomain/whats-new/): Useful details on otherwise confusing dates created by changing copyright law.
Open Music Archive: Well tagged British site with many, many PD songs (in Great Britain) entered which are in the folk vein. (http://openmusicarchive.org/contact.php)
PD Hymns (https://www.pdhymns.com/index.htm): Just what the name implies, a l-o-n-g list of PD hymns.
PD Info (https://www.pdinfo.com/index.php) This site has generally good information - and a lot of it. I found little to argue about. Yes, it is commercial, but it's far more. What they sell is focused upon material to help you defend yourself in a suit should that ever be needed. The text, while correct, is skewed a bit towards warning you of the dangers of illegally using copyrighted material. Which is not a bad thing. It also has an extensive list of PD music, slanted more toward pop than folk. Note that their alphabetical order is not perfect - nor is my own.
St. Clair County Community College (https://esearch.sc4.edu/publicdomain/music) Good links.
University of Cincinatti (https://guides.libraries.uc.edu/copyrightfaq/music) Copyright basics. Lots of links.
University of Michigan (https://guides.lib.umich.edu/permissions): Though designed for those associated with the University, it offers excellent information for anyone.
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