Providers
- Abraham Lincoln Presidential Library and Museum (22)
- American Antiquarian Society (30)
- American Archive of Public Broadcasting (25)
- American Museum of Natural History (109)
- Arlington National Cemetery (22)
- Association for Diplomatic Studies and Training (29)
- Center for History and New Media (26)
- Center for Teaching the Rule of Law (22)
- Civil Rights Movement Archive (102)
- Connecticut Humanities (49)
- National Consortium for Teaching about Asia (20)
- National Endowment for the Arts (27)
- National Endowment for the Humanities (375)
- National Gallery of Art (17)
- National Humanities Center (1099)
- National Park Service (33)
- New American History (48)
- New-York Historical Society (312)
- Norman B. Leventhal Map & Education Center at the Boston Public Library (29)
- North Carolina Museum of Art (70)
- PBS LearningMedia (641)
- PBS Learning Media (79)
- Philosophy Learning and Teaching Organization (PLATO) (24)
- Teachers Institute of Philadelphia (44)
- TeachRock (120)
- The Eleanor Roosevelt Papers Project (25)
- The Huntington Library, Art Museum, and Botanical Gardens (36)
- The National Archives (UK) (183)
- The Open Anthology of Literature in English (17)
- TPS Eastern Region (25)
- UC Berkeley History-Social Science Project (49)
- UNC-Duke Consortium in Latin American and Caribbean Studies (26)
- UNC World View (53)
- U.S. Census Bureau (62)
- U.S. Citizenship and Immigration Services (15)