Wikipedia:Public domain

The public domain is generally defined (e.g. by the U.S. Copyright Office) as the sum of works that are not copyrighted, i.e.

However, there is no such thing as the public domain on the Internet. International treaties, like the Berne Convention, are not self-executing and do not supersede local law. There is no globally valid "International Copyright Law" that would take precedence over local laws. Instead, signatory countries of the Berne Convention have adapted their laws to comply with the minimum standards set forth by the treaty, often with stronger provisions than required. Whether or not something is copyright-free in some country depends on the laws of individual countries.

The U.S. Copyright Law explicitly makes clear that the Berne Convention is just a treaty, not some "super-law" that would take precedence over U.S. law: 17 USC 104(c) states that

U.S. federal government works (including works prepared by the governments of the District of Columbia, Puerto Rico, and U.S. organized territories) are not eligible for copyright protection (17 USC 105). It is not clear whether this applies world-wide -- see the CENDI Copyright FAQ list, 3.1.7 and a discussion on that at the LibraryLaw Blog. The U.S. government themselves state that they "may assert copyright outside of the United States for U.S. government works."

In practice, this means that much material on *.gov and *.mil, as well as material on some *.us web sites (such as the sites of the U.S. Forest Service), are in the public domain. Please note that not all such material is in the public domain, though:

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