Each of these lists is is alphabetical order by site, not by importance or usefulness, so browse the whole list.
American Memory Collection (Motion Picture and Television Reading Room, Library of Congress)
http://www.loc.gov/rr/mopic/ndlmps.html
Films included in this collection are mostly in the public domain, however, please verify the status before using a film.
Moving Image Archive (Archive.org)
http://archive.org/details/movies
This site allows you to either stream or download film materials from a variety of sources. Movies you'll find on this site are either covered under Creative Commons licenses or are in the public domain. Please double check to be sure.
Archive Torretn Movies (Archive.org)
http://archive.org/details/bittorrentmovies
More than 9,000 videos are available from the Internet Archive via BitTorrent.
The Prelinger Archives (via Archive.org)
http://archive.org/details/prelinger
Prelinger Archives was founded in 1983 by Rick Prelinger in New York City. Over the next twenty years, it grew into a collection of over 60,000 "ephemeral" (advertising, educational, industrial, and amateur) films. In 2002, the film collection was acquired by the Library of Congress, Motion Picture, Broadcasting and Recorded Sound Division. Prelinger Archives remains in existence, holding approximately 5,000 digitized and videotape titles (all originally derived from film) and a large collection of home movies, amateur and industrial films acquired since 2002. Its goal remains to collect, preserve, and facilitate access to films of historic significance that haven't been collected elsewhere. Included are films produced by and for many hundreds of important US corporations, nonprofit organizations, trade associations, community and interest groups, and educational institutions. Make sure you read the "rights" section on the page and in particular note, "the CC Public Domain license refers to the public domain status of the films, but not necessarily to every element that a film may contain."
Sites selected for this list were included because the majority of the links provide access to public domain map content.
Hathi Trust Digital Library
http://catalog.hathitrust.org/Search/Advanced
Find works of all different formats by using the advanced search
feature. You can locate items that are in the public domain by limiting
your search to "full view only" and/or limiting by dates (pre-1923, for
instance. The Hathi Trust has a great and fairly concise explanation of public domain in the United States in comparison to other countries.
"Maps Library Guide" by Jennie Burroughs and Donna McCrea of the Mansfield Library
http://libguides.lib.umt.edu/maps
Contains maps by topic: historic, scientific, topographic, Montana maps, etc. Ones created by U.S. Government Agencies by U.S. Government employees are in the public domain. You need to verify the copyright status of other maps you find by using this guide.
Perry-Castañeda Library Map Collection-- University of Texas Online
http://www.lib.utexas.edu/maps/
Includes maps from all over the world. According to their frequently asked questions many of their maps are in the public domain. The ones that are not are clearly marked as being protected under copyright law.
"Sources of Public Domain Maps" Public Domain Sherpa
http://www.publicdomainsherpa.com/public-domain-maps-resources.html
Another recommended link from the Public Domain Sherpa site. Site provides many more links to sites where you can access public domain maps.
This selective lists includes sources for non-fiction, fiction, poetry, and drama.
Eldritch Press
http://eldritchpress.org/
While this may not be the longest list of public domain materials, it does contain American literature, English literature, and literature in English translation from across the world.
Europeana
http://www.europeana.eu/portal/
Contains links to a wide range of digitized materials held in European libraries and museums-- some of which are in the public domain. Be sure to check the rights information on the files you view or use.
Google Books
http://books.google.com/advanced_book_search
Not all material listed here is in the public domain, but you can search for books and magazines published prior to 1923 by using the Google Books Advanced Search.
Government Documents
http://www.gpoaccess.gov/index.html
http://www.gpo.gov/
Find works created by Federal Government agencies.
Hathi Trust Digital Library
http://catalog.hathitrust.org/Search/Advanced
Find works of all different formats by using the advanced search feature. You can locate items that are in the public domain by limiting your search to "full view only" and/or limiting by dates (pre-1923, for instance. The Hathi Trust has a great and fairly concise explanation of public domain in the United States in comparison to other countries.
Internet Archive: Text Archive
http://www.archive.org/details/texts
Some of the texts on this site also contain Creative Commons licensed works. Contains quite a bit of content.
Library of Congress
http://www.loc.gov
In addition to other online and print collections of public domain works, also be sure to check out the Library of Congress's Digital Collections which can provide access to public domain materials over the Internet on a variety of topics. Please also be sure to double check that the material you use is actually in the public domain. The introductory web pages for each collection typically contains a link to a copyright page-- here is an example from the National American Woman Suffrage Collection.
Project Gutenberg
http://www.gutenberg.org/wiki/Main_Page
Be sure to have a look at Project Gutenberg's License page, which explicitly makes a distinction between using the raw public domain content in its e-books and Project Gutenberg's trademarked and licensed content. You can read this information-- in layman's terms-- under the heading "Public Domain Books."
Wikipedia
http://en.wikipedia.org/wiki/Wikipedia:Public_domain_resources
This site consists of a list of links to other Internet sites which provide access to public domain works. I recommend this site with a bit of caution in that you should verify the public domain status of any materials you locate.
This selective list contains links that can provide you with access to art collections (original art objects that may be in the public domain) as well as art reproductions that could be in the public domain. While it can be fairly easy to locate actual works of art in the public domain, reproductions of public domain art works may not be in the public domain. As always, please verify the copyright status of whatever material you'd like to use for your project.
Some canned Google searches that may prove helpful:
1. Art museums and galleries under the domain .org
2. Art museums and galleries under the domain .edu
Locating Art reproductions, photographs, other images in the Public Domain:
This list will help lead you to public domain art reproductions, photos, and other images. Again, it's important to remember that even though an art object might be in the public domain, its reproduction may not be. Here are a couple of resources to consult which further explain this potential problem area when using reproductions of public domain visual works.
Art & Art History LibGuide
I put together this guide to help art & art history students with research including locating a variety of images. Some of these links may take you to public domain image reproductions.
"Finding and Using Public Domain Photographs" Public Domain Sherpa
This page is from an informative public domain site written by an independent entrepreneur/attorney. Author provides a lengthy list of sites that provide access to public domain photos because the original work's copyright duration expired or the original work was created by a U.S. Government agency.
U.S. Government's Official Web Search (for images)
U.S. Government Photos and Images
Use these sites to help you search for images created by the U.S. Government.
Flickr: Public Domain
This is a newer group pool for Flickr where contributors are dedicating their images to the public domain. There are also other groups in Flickr that do similar things about a more specific topic. If you have images that you'd like to dedicate to the public domain, you can also join the group. As always, be sure to verify the copyright status before using any of these images.
This site not only provides access to Creative Commons-licensed images, but also to reproductions of public domain images. Recently they've been teaming up with the National Archives to provide access to thousands of photos.
This guide on using public domain materials, Creative Commons licensed materials, and copyright law is provided for informational purposes only. I am not a lawyer and cannot provide legal advice. None of what you read in this tutorial should be construed as legal advice. Should you require legal advice, please contact an attorney.
This guide is based on a guide orginally created by Tammy Ravas, Visual and Performing Arts Librarian and Media Coordinator of the Mansfield Library at the The University of Montana. All errors are, of course, my own.
Sites selected for this list mostly provide access to public domain sheet music.
Choral Public Domain Library
http://www1.cpdl.org/wiki/index.php/Main_Page
This site provides access to public domain choral sheet music as well as some contemporary works where the composer wished to share scores for download. Please be sure to verify the copyright status of works you wish to use.
Hathi Trust Digital Library
http://catalog.hathitrust.org/Search/Advanced
Find works of all different formats by using the advanced search feature. You can locate items that are in the public domain by limiting your search to "full view only" and/or limiting by dates (pre-1923, for instance. The Hathi Trust has a great and fairly concise explanation of public domain in the United States in comparison to other countries.
Harvard College Library (Online Resources for Music Scholars)
http://guides.hcl.harvard.edu/onmusic
This site provides a list of links to institutions who digitize sheet music for the open web. Some of the materials that they list may be subscription-only for the Harvard community. Please verify that the material is actually in the public domain.
Historic American Sheet Music (Duke University)
http://library.duke.edu/digitalcollections/hasm/
Most of the materials here are in the public domain, but please check the dates or other features to be certain.
International Music Score Library
http://imslp.org/
Well-organized wiki-based site for accessing public domain and a few Creative Commons musical works.
Internet Archive
http://www.archive.org/
Contains some score collections. Locate these materials using a keyword search. As always, please be sure to verify the public domain or Creative Commons status of the work.
Lester S. Levy Collection of Sheet Music
http://levysheetmusic.mse.jhu.edu/
Contains popular American sheet music from 1780 through 1980. Just from looking at the range of dates, not everything is in the public domain; be sure to check dates and other features.
Musopen: Free Public Domain Classical Music
http://musopen.org/
This resource complements searhcing in IMSLP and/or Mutopia. You can access public domain scores here. There are also recordings available from this site, but they could still be under copyright or are under a Creative Commons license. You need to create a free account to access the recordings.
Music for the Nation: American Sheet Music (Library of Congress)
http://memory.loc.gov/ammem/smhtml/smhome.html
Sheet music collection dating from 1870-1885. Most of the content should be in the public domain, but you need to verify it.
Public Domain Information Project
http://www.pdinfo.com/about.php
This site is more proprietary in nature, but provides a good list of musical works that are in the public domain.
Sheet Music Collections (Sheet Music Consortium)
http://library.duke.edu/music/sheetmusic/collections.html
Provides links to libraries and research institutions that provide web access to scores. Many of these are in the public domain, but it's always a good idea to verify.
Sibley Music Library (Eastman School of Music/University of Rochester) Musical Scores
https://urresearch.rochester.edu/viewInstitutionalCollection.action?collectionId=63
Contains over 8,500 public domain scores in its digital collections and continues to grow! You can subscribe to an RSS feed to see what will be added next (copy and paste this link into your favorite RSS reader: https://urresearch.rochester.edu/viewInstitutionalCollectionRss.action?collectionId=63).