The American Historical Association is the leading professional organization for historians in the United States.

The Organization of American Historians is the leading professional organization for historians who research and write about American history.

H-net is a scholarly networking tool for the humanities and social sciences.
 

The National Center for History in the Schools hosts the national history standard guidelines for grades K-12.

Google Books has made tens of thousands of full-text books available for free.

http://www.hathitrust.org/

HathiTtrust is another digital library. Fred Smith promises that it is even easier to use than Google Books.

Historian Steven Mintz served as lead historian for this useful set of digital resources for history teaching at all levels.

The Avalon Project, hosted by Yale University, is a key source for documents pertaining to the histories of law and diplomacy.

Eyewitness to History contains eyewitness accounts going back to ancient times.

The University of Wisconsin hosts this site, which contains a hundred years of US State Department records covering 1861-1960.

This is the best single site for research about America's presidents. For twentieth century Presidents in particular, you may also want to look at the websites hosted by individual Presidential Libraries.

 

 

The Research Society for American Periodicals has created a fabulous research guide for 19th century newspapers and magazines.

 

 

The Library of Congress' American Memory is a major repository of primary documents pertaining to American history. Its photo collection is especially strong.

 

 

Mount Holyoke has put together a marvelous collection of World War II documents.

 

 

This is the Navy website for Pearl Harbor. A wonderful starting place for research on this topic.

 
http://www.densho.org

This is a website dedicated to preserving the oral histories of Japanese-Americans who had been interned during World War II.

http://cehs.unl.edu/ushistory/online/native/primary.html

This is good starting place for researching Native-American history.

 

 http://scriptorium.lib.duke.edu/wlm/

This is a great site for primary documents related to radical feminism.

 
http://library.duke.edu/digitalcollections/adaccess/

Duke University has created a fabulous database of advertisements. They have been beautifully digitized.

http://quod.lib.umich.edu/m/moagrp/

This is a great starting place for researching 19th century American history from the antebellum period to the end of Reconstruction.

http://www.time.com/time/archive

Time Magazine has a searchable archive of its articles going back to 1923.

http://www.historicalvoices.org/flint/

The Flint Sit-Down Strike Audio File contains oral histories related to this pivotal moment in the history of unionism.

http://www.archive.org/

Internet Archive has not only full-text content, but also videos.

http://www.ourdocuments.gov/content.php?page=milestone

The National Archive's 100 Milestone Documents in American History.

http://www.fordham.edu/halsall/mod/modsbook.html

Fordham University hosts the Modern History Sourcebook, a great place to go for primary documents related to American as well as European history.

http://www.lib.washington.edu/subject/history/tm/women.html

University of Washington has put together this site of links to online resources in women's history.

http://guides.lib.washington.edu/content.php?pid=78827&sid=583725

The University of Washington has done the same for African-American history.

 

This list is based on Reference Librarian Fred Smith's "Study of History Web Research Guide." With additions by Jason Martinek.