Hundreds of books are challenged in schools and libraries in the United States each year. A challenge is an attempt to remove or restrict materials, while a banning reflects the actual removal of those materials. The American Library Association (ALA) provides confidential support to teachers and librarians and tracks challenges that occur. ALA recorded 348 challenges in 2010 but estimates that this reflects only 20-25% of actual incidents, as most challenges are never reported.
This map is drawn from cases documented by ALA and the Kids' Right to Read Project, a collaboration of the National Coalition Against Censorship and the American Booksellers Foundation for Free Expression.