More Maps Are in the Public Domain Than You Think

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By Linda Musser

Most of us know the general rules for U.S. copyright – that works are copyrighted for 95 years after which they move into the public domain. For many years the year to remember was 1923 – as in only works published prior to 1923 were in the public domain. Beginning with 2019, however, the old date for copyrighted works annually moves forward one year on January 1 … thus, in 2019, works published prior to 1924 are in the public domain. While it is heartening that ‘new’ old works are now annually entering the public domain, it will be a long time before many older works will become available online – or will it?  A closer examination of the copyright status of maps reveals some promising possibilities.

First, it is useful to remember that a large percentage of maps published in the United States are already in the public domain because they were published by the federal government (e.g, Census maps, USGS topographic maps, etc.).  For maps that were copyrighted, many did not have their copyright renewed, something that the law required for many years. Essentially, U.S. copyright law required that works have their copyright renewed in a specific period 27 years after their initial copyright date. If the renewal did not occur within that time frame or lacked proper copyright language, then the work would revert to being in the public domain. U.S. law was later changed to make renewals automatic but the more restrictive requirement remains in place for works published in the United States prior to 1964.

Research by Wilkin (2017) based on works in the HathiTrust Digital Library found that over 50% of works published in the U.S. between 1923 and 1964 were in the public domain due to lack of proper copyright renewal. An earlier work on the copyright renewal of Sanborn maps (Musser, 2014) found similar percentages while more recent research (Musser in press) indicates that, if Sanborn maps are excluded from consideration, the copyright renewal rate for maps published in the U.S. between 1923 and 1964 is less than 10%.

From 1924 through 1963, nearly 81,000 maps were copyrighted in the United States. Table 1 illustrates the limited range of copyright holders who took the time to renew their copyrights for part of this period. The Sanborn Map Company alone renewed over 6000 map copyrights over a twenty-year period however they were exceptional in this, as illustrated by table 2.

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Table 1.  Sample of copyright holders who renewed a copyright for a map for a period from 1951-1962. (Specific titles and more years are available by consulting the CCE.)

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Table 2: Top five map copyright owners who renewed map copyrights from 1950-1969.

For those interested in determining the copyright status of older maps in their collections, there are several tools to use. First among them is the Catalog of Copyright Entries (CCE), which documented works registered for U.S. copyright and works that had their copyright renewed. Scans of the CCE through 1978 are available from the Online Books Page at the University of Pennsylvania. From this page, there are links by year then by format, then links to the renewal lists. From 1978 onwards, rather than use the CCE, the U.S. Copyright Office maintains a Copyright Catalog where renewals can be searched. Thus for works copyrighted from 1924-1950, the CCE must be used to search copyright renewals after which the online Copyright Catalog can be used. Since copyright holders had a 12-month window in which to renew their works, searchers must check several years of the CCE. This is necessary because the CCE was published biannually and late renewals could appear in the publication as much as two years after one might expect. To determine which years of the CCE to examine, use the following formula:

Year of original copyright + 27 = year of earliest copyright renewal (+ check 2 years following)

Example of item copyrighted in 1931:  1931 + 27 = 1958 CCE plus check CCE volumes in 1959 and first volume for 1960.

Example of two copyright renewalsFigure 1: Two map copyright renewals from the first part of the 1959 Catalog of Copyright Entries. Both works were renewed on Feb. 6, 1959. The original copyright year for the first work was 1932 while the second work was originally copyrighted in 1931.

Although searching for a copyright renewal is relatively easy, there are other issues to take into consideration when exploring the copyright status of maps. These include whether the map was published first outside the U.S., is a translation, a revised edition, and so on. It is important to be alert for third party works when examining the copyright status of maps, such as inserts or photographs that might have separate copyrights. Buildings plans and other architectural works, on the other hand, were not copyrightable prior to the 1990s.  Each of these nuances can affect the copyright status of the work. More detailed, step-by-step guidelines for determining copyright status can be found in the work by Levine “Finding the Public Domain” or Peter Hirtle’s website “Copyright Term and the Public Domain in the United States” (see list of resources below).

To summarize, the process for checking the copyright status of pre-1964 U.S. published works is fairly straightforward.  Major projects such as that by the HathiTrust have focused on books and serials and users worldwide have reaped the benefits of gaining access to over 700,000 volumes that, based on publication date alone, had been thought to still be under copyright protection (HathiTrust, 2019). There is no equivalent project underway for maps but it is likely that the majority of maps copyrighted in the United States prior to 1964 are now in the public domain due to lack of copyright renewal.

Useful Resources for Investigating Copyright Status:

Hirtle, Peter, 2019.  Copyright Term and the Public Domain in the United States (Accessed 25 October 2019)

Levine, Melissa, et al., 2016. Finding the Public Domain: Copyright Review Management System Toolkit.  University of Michigan, Ann Arbor, MI. (Accessed 25 October 2019)

U.S. Copyright Office, 2013. How to Investigate the Copyright Status of a Work. 12 p. (Accessed 25 October 2019)

For more background, see also:

Demas, Samuel and Brogdon, J.L., 1997. Determining Copyright Status for Preservation and Access: Defining Reasonable Effort. Library Resources & Technical Services 41(4):323-334.  DOI:


HathiTrust, 2019. Copyright Review Program. (Accessed 25 October 2019)

Musser, Linda, 2014.  Copyright Status for Sanborn Maps. base line 35(4):25-26.

Musser, Linda, in press. A Study of the Copyright Renewal Rate for Maps. Issues in Science & Technology Librarianship.

Wilkin, John P., 2017. How Large is the “Public Domain”? A Comparative Analysis of Ringer’s 1961 Copyright Renewal Study and HathiTrust CRMS Data. College & Research Libraries 78(2):201-218. DOI:

Linda Musser
Head of Fletch L. Byrom Earth And Mineral Science Library
Penn State University

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