This is a growing list of publically available digital archives in American politics, society, and culture, for use in teaching and research--though many more digital archives are available through public and academic libraries. For more, see my 2009-2010 blog on digital archives, The Lazy Scholar.
Advertising
Emergence of Advertising in America: 1850-1920 (Duke)
Ad*Access (1911-1955)
AdViews: A Digital Archive of Vintage Television Commercials (1950s-80s; Duke)
Victorian Tradecards (1880s-1910s; Miami U in Ohio)
African-American History, Politics, and Culture
African-American Film Collection (SMU)
Behind the Veil: Documenting African-American Life in the Jim Crow South (Duke)
Black World/Negro Digest (1960s/70s; Google Books)
Civil Rights Digital Library (Georgia)
Civil RIghts in a Northern City: Philadelphia (1960s; Temple)
Civil Rights in Mississippi Digital Archive (1960s; University of South Mississippi)
The Crisis (1910s-present; Google Books)
Ebony (1950s to present; Google Books)
Ebony Jr (1970s/80s; Google Books)
Freedom on Film: Civil Rights in Georgia (University of Georgia)
Jet (1950s-2005; Google Books)
Mississippi Freedom Summer Digital Archive (1964; Miami)
Asian-American History, Politics, and Culture
The Chinese in California (1850-1925; Library of Congress/UC Berkeley)
Chinese Railroad Workers in North America (Stanford)
Densho Japanese American Archives (1900s to 1980s)
Japanese American Relocation Digital Archives (Calisphere)
Korean American Digital Archives (USC)
Cities
New York Real Estate Brochure Collection (1920s-70s; Columbia)
Education
Children's Historical Literature Collection (University of Washington)
Traveling Culture: Circuit Chautauqua in the Twentieth Century (1904-1932; University of Iowa)
Environmentalism
J.N. ‘Ding’ Darling Cartoons (University of Iowa)
Food
Buttolph Menu Collection (1850s on; NYPL)
Culinary History Collection (Virginia Tech)
Gebhardt Mexican Foods Records and Exhibit (1896-1988; UT San Antonio)
Home Economics Archive (1850-1950; Cornell)
Menus Collection (1889-2003; University of Washington)
Recipe for Victory: Food and Cooking in Wartime (1910s; University of Wisconsin)
Restaurants of New York (Museum of the City of New York)
Immigration
Aspiration, Acculturation, and Impact: Immigration to the United States, 1789-1930 (Harvard)
Jewish-American Culture
American Jewess Magazine (1895-1899) Jewish Women's Archive/MSU)
American Jewish Committee Oral History Collection (NYPL)
American Jewish Historical Society, New England
Washington State Jewish Archives (University of Washington)
Labor and Industry
19th and 20th Century Labor Prints (Georgia State University)
Drawing on the American Labor Movement: Labor History Cartoons of Fred Wright (1956-61; University of Pittsburgh)
Industries and Occupations Photographs (University of Washington)
J.C. Penney The Dynamo Magazine Collection (1917-1932; SMU)
Southern Labor Archives (Georgia State University)
Latino History, Politics, and Culture
Chicana por mi Raza: Uncovering the Hidden History of Chicana Feminism
Latino Cultural Heritage Digital Archive (CSU Northridge)
Los Angeles Latino Families Photo Project (1910s-90s; UCLA)
Mexican American Family and Photo Collection (Houston Public Library)
LGBTQ
Georgia LGBTQ Collection (Georgia State University)
Gran Fury (1980s; NYPL)
Milwaukee Transgender Oral History Project
Outspoken: Oral History from LGBTQ Pioneers
Outweek (1980s/90s)
ONE National Gay and Lesbian Archives
UT San Antonio LGBTQ Collections
Medicine and Public Health
Historical Medical Poster Collection (Yale)
Patent Medical Cards (UCLA)
Music
Cylinder Preservation and Digitization Project (UCSB)
Historic American Sheet Music (1850-1920; Duke)
Hip Hop Collection (Cornell)
Recorded Sound Archives (including Judaica Sound Archives; Florida Atlantic University)
Voices from the Dust Bowl (1940-41; Library of Congress)
Native American History, Politics, and Culture
After Columbus: 400 Years of Native American Portraiture (NYPL)
American Indians of the Pacific Northwest Collection (University of Washington)
Carlisle Indian School Digital Resource Center (Dickinson)
Duke Collection of American Indian Oral History (1960s/70s, University of Oklahoma)
McKenney and Hall Lithographs (1836-44, University of Washington)
Native American Language Children's Books (University of New Mexico)
Native American Constitution and Law Digitization Project
New England Native American Papers Database
Photography
Documentary
Photogrammar (FSA-OWI photographs, 1935-1945; Yale)
Ronald Reis Photographs (1950s/60s; Duke)
Stanley Kubrick LOOK Photographs (1945-50; Museum of the City of New York)
William Gedney Photographs (1970s counterculture, gay rallies; Duke)
Portrait
Michael Francis Blake Photographs, 1912-1934 (Duke)
Lawrence T. Jones III Texas Photographs , 1846-1945 (SMU)
Stereographs
Banks McLaurin, Jr. Stereograph Collections (Southern landscapes, domestic scenes; military; SMU)
Occidental College War Stereographs (Civil War, Spanish-American War, World War I)
Stereocard Collection (University of Washington)
Politics
Government Publications from World War II (SMU)
The Living Room Candidate: Presidential Campaign Videos, 1950-2012 (Museum of the Moving Image)
Propaganda Posters (Washington State University)
Vietnam War Era Ephemera (University of Washington)
Popular Culture
Dime Novel and Story Paper Collection (Stanford)
Religion
Protestant Family Magazines (Duke)
Slavery
Born in Slavery: Slave Narratives from the Federal Writers' Project, 1936-1938 (Library of Congress)
North American Slave Narratives (UNC)
Slaves and the Courts, 1740-1860 (Library of Congress)
Voices from the Days of Slavery (Library of Congress)
South/Southeast Asian American Culture and Politics
Immigration Arrival Investigation Case Files, 1884-1944 (South Asian American Digital Archive)
South Asian American Digital Archive
South Asian Oral History (University of Washington)
South East Asian American Digital Archive (UC Irvine)
Southern Life and Culture
H. Lee Waters' Film Collection (1936-1942; Duke)
Hugh Mangum Itinenerant Photography (1890s-1920s; Duke)
Theater and Performance
19th Century Actors and Theater Photographs (University of Washington)
The Carpa Cubana Collection and the Sabino Gomez Photograph Collection (Witte Museum)
Billy Rose Theater Collection Photograph File (NYPL)
Broadway Productions Photograph Collection (Museum of the City of New York)
J. Willis Sayre Photographs (University of Washington)
Prior and Norris Vaudeville Troupe Photographs (University of Washington)
Transportation
Taking the Wheel: Manufacturers' Catalogs from the First Decade of American Automobiles (1909; NYPL)
Women's Politics, Labor, and Culture
Women's Liberation Movement Print Culture (1960s and 70s; Duke)
Women Working, 1800-1930 (Harvard)
Working Mother Magazine (1970s-2000s; Google Books)
Video
San Francisco Bay Area Television Archive (San Francisco State University)
Sulphur Springs Collection of Pre-Nickelodeon Films, Hamon Arts Library (SMU)
Tyler, Texas Black Film Collection (SMU)
Major Digital Archives
Digital Public Library of America
DIY History (University of Iowa)
Museum of the City of New York
University of California, Los Angeles