Ancient History Encyclopedia - Write articles or definitions for this widely used website
Journal of the American Revolution - Emerging scholars can contribute long and short articles to this web-based journal.
BlackPast.org - Join more than 700 volunteer contributors in this online encyclopedia on African American history
Freedom on the Move - Transcribe runaway slave ads. These preserved the details of individual lives--their personality, appearance, and life story. Taken collectively, these ads constitute a detailed, concise, and rare source of information about the experiences of enslaved people.
Beyond Words - A WWI newspaper project from the Library of Congress. Help make the historical newspapers more searchable by doing one of three tasks: marking, transcribing and verifying.
Citizen Archivist - Transcribe Federal documents from the National Archives and Records Administration
Smithsonian Digital Volunteer - Join 9,000+ volunteers to transcribe and make searchable the field notes, diaries, ledgers, logbooks, currency proof sheets, photo albums, manuscripts, biodiversity specimens labels from Smithsonian Collections
World Memory Project - Help make these Holocaust victims' records searchable online and restore the identities of people the Nazis tried to erase from history, one person at a time. (Download required to participate)
New York Historic Menus - Transcribe and correct the dishes found in New York City menus of the past
American Soldier Project - Uncensored, handwritten reflections of military service from WWII soldiers collected by the Army Research Branch. This is a collaboration from Virginia Tech.
Anti-Slavery Activist Manuscripts - Help transcribe the influential, anti-slavery writings of the 19th century. Hosted by the Boston Public Library
Library of Congress Transcriptions - Transcribe, review, and tag important historical documents