The Massachusetts Historical Society

Founded in 1791, the Massachusetts Historical Society (MHS) is an independent research library and manuscript repository. Its holdings encompass millions of rare and unique documents and artifacts vital to the study of American history, many of them irreplaceable national treasures. In the two centuries since the founding of the MHS, its mission has remained constant: to collect, preserve, make accessible, and communicate manuscripts that promote the study of Massachusetts and the nation. The institution today encompasses five programmatic areas: library, publications, research programs, The Adams Papers, and education and public programming.

http://www.masshist.org