* American Studies & Ethnicity 

American Centuries: View from New England

American Local History Network

American Social History Online

Brief Timeline of American Literature and Events, pre-1650 to 1920

Brown University Steering Committee on Slavery & Justice

Chronicling America: Historic American Newspapers (Library of Congress)

Chronology of US Historical Documents

Digital History

Disability History Museum Library

Doc Heritage

Documenting the American South

E Pluribus Unum Project: America in the 1770s, 1850s, and 1920s

eHistory Primary Sources

Electronic Documents in History

Electronic Text Center: The Modern English Collection (1500-present)

Emergence of Advertising in America: 1850-1920

Emigration and Immigration to the United States, 1789-1930

Explore PA History

Gilder Lehrman Institute of American History

Harpweek (1857-1912)

Historical Map Web Sites

Immigration to the United States, 1789-1930

In Motion: The African-American Migration Experience

Internet Women's History Sourcebook

Louisiana Digital Library

Ohio Memory

Portal to Texas History

Presidential Recordings Program

Presidents of the United States (POTUS)

Public Papers of the Presidents of the United States

Regional Oral History Office (UC-Berkeley, Bancroft Library)

Uncle Tom's Cabin and American Culture

Windows on the Past (Cornell University Library)

Women Working, 1800-1930

American Memory -- This Library of Congress collection provides free and open access to a wide range of primary source material documenting American history and culture, including text, sound recordings, still and moving images, prints, maps, and sheet music. Its collections are as follows:
Advertising (6 Collections)
African American History (17 Collections)
Architecture and Landscape (9 Collections)
Cities and Towns (13 Collections)
Culture and Folklife (35 Collections)
Environment and Conservation (3 Collections)
Government and Law (24 Collections)
Immigration and American Expansion (13 Collections)
Literature (7 Collections)
Maps (11 Collections)
Native American History (6 Collections)
Performing Arts and Music (33 Collections)
Presidents (14 Collections)
Religion (8 Collections)
Sports and Recreation (10 Collections)
Technology and Industry (14 Collections)
War and Military (29 Collections)
Women's History (7 Collections)

American Presidency Project

Avalon Project, Document Collection, Yale Law School

Densho.org -- Densho documents the experience of Japanese Americans who were incarcerated during World War II, providing access to digitized internment camp newspapers, firsthand accounts, video interviews, and more (you'll need to sign up for a free account to use this).

Historical Census Browser

History Matters -- This site, created by the American Social History Project/Center for Media and Learning (CUNY) and the Center for History and New Media (George Mason University) contains a wealth of primary source material, research guidance, and annotated Web links.

Library of Congress (in addition to the American Memory links listed above). Some of its many collections include:
American Folklife Center
Chronicling America: American Historic Newspapers
Religion and the Founding of the American Republic
Declaring Independence: Drafting the Documents
The Gettysburg Address
Library of Congress Web Archives

Making of America (University of Michigan)

Making of America (Cornell University)

New York Public Library Digital Collections
Africana & Black History (image collection)
African American Women Writers of the 19th Century (text collection)
After Columbus: Four-hundred Years of Native American Portraiture (image collection)
American Popular Song Sheet Covers, 1890-1922 (image collection)
Charting North America: Maps from the Lawrence H. Slaughter Collection and Others (image collection)
Cigarette Cards: ABCs (image collection)
Civil War Medical Care: Photographs from the United States Sanitary Commission Collection, 1861-1872 (image collection)
NYPL Digital Gallery (image collection)
Early Landscape Photography of the American West (image collection)
Ellis Island Photographs, 1902-1913 (image collection)
Lewis Wickes Hine: Documentary Photographs, 1905-1938 (image collection)
In Motion: The African-American Migration Experience (text and image collections)
The "Pageant of America" Photograph Archive (image collection)
Picturing America, 1497-1899: Prints, Maps, and Drawings (image collection)
Surveyors of the American West (text collection)
Taking the Wheel: Manufacturers' Catalogs from the First Decade of American Automobiles
World War I Photograph Albums and Postcards

NUCMC Repositories of Primary Sources

Primary Source Materials: Moving Images and Sound Recordings  This site, developed by the University of California-Berkeley Library, provides information about and some access to sound recordings, non-fiction films and television resources, radio programs, and musical primary sources

University of Washington
Native American History

Voice of the Shuttle  Extensive portal of History sites

I am most grateful to Theresa Mudrock of the University of Washington Libraries for her extensive collection of primary source links, from which I learned of many of the resources in this guide.

To view her History resources, go to http://www.lib.washington.edu/subject/history.