Public domain maps are geographical maps that are not protected as intellectual property under copyright laws in a particular country. Maps can be protected under copyright, much like other creative or artistic works, but those that are not protected by copyright are considered part of the public domain. There are different ways in which a map can be within the public domain, including maps made by the government and maps that use generally available information. Public domain maps can also include old maps for which copyright ownership has expired.
A map is typically considered to be protected as the intellectual property of the person or company that creates or commissions it. This places such maps under copyright protection, much like a work of art, film, or piece of literature and requires that permission from the copyright owner must be gained prior to the use of such maps. Public domain maps, however, are maps that are not protected under copyright law. This means that public domain maps can be used freely by anyone who wishes to do so, though it is still possible that someone can charge money for access to a copy of a public domain map that he or she owns.
There are a few different ways in which maps can become public domain maps, though the most common is for a map to be created by a government agency. While copyright laws can differ among countries, in the US, for example, maps created by the federal government are part of the public domain. This means there are hundreds, if not thousands, of maps that have been created by the government and can be used freely.
Public domain maps can also include those created using generally available information. Someone who sketches out the outline of a country, or of the borders between states and provinces, has typically not met the originality requirements for copyrighted works. Similarly, map keys, color codes, and geographical terrain markers are typically considered within the public domain and are not protected by copyright.
There are also some public domain maps that were once protected under copyright ownership, but which no longer are. Copyrights eventually expire, usually within a number of decades after the creation of the protected work, and most maps created before 1923 are no longer protected under copyright. Previous copyright laws also required that any map under copyright include a notice of copyright, so most maps printed prior to 1989 in the US without a copyright notice are public domain maps.