The federal government has been collecting data on public libraries for over two decades via a national census of such institutions that was first administered by the U.S. Department of Education and then, beginning in 2006, by the Institute of Library and Museum Services (IMLS). A public library is defined by IMLS as an entity that was established under state enabling laws or regulations to serve a community, district, or region, and that provides at least the following:
- an organized collection of printed or other library materials or a combination thereof;
- paid staff;
- an established schedule according to which services of the staff are available to the public; and
- the facilities necessary to support such a collection, staff, and schedule.
A library may be a single outlet or a library system comprising a central library, branches, and, in some cases, bookmobiles and book-by-mail operations. In fiscal year 2010, 8,951 public libraries operating in the 50 U.S. states and the District of Columbia met the criteria above. [D. W. Swan, J. Grimes, T. Owens, R. D. Vese Jr., K. Miller, J. Arroyo, T. Craig et al., Public Libraries Survey: Fiscal Year 2010, IMLS-2013-PLS-01 (Washington, DC: Institute of Museum and Library Services, 2013), 7.]
