ALA is officially incorporated under the laws of the state of Massachusetts.

"Be it known, that whereas Justin Winsor, C. A. Cutter, Samuel S. Green, James L. Whitney, Melvil Dui, Fred B. Perkins and Thomas W. Bicknell, have associated themselves with the intention of forming a corporation under the name of the American Library Association for the purpose of promoting [the] library interests [of the country] throughout the world by exchanging views, reaching conclusions, and inducing cooperation in all departments of bibliothecal science and economy; by disposing the public mind to the founding and improving of libraries; and by cultivating good will among its own members, and by such other means as may be authorized from time to time by the Executive Board or Council of the American Library Association, and have complied with the provisions of the statutes of this Commonwealth in such case made and provided, as appears from the certificate of the President, Treasurer and Executive Board of said corporation, duly approved by the Commissioner of Corporations, and recorded in this office."

Read more of the 1879 Charter