Colonial America: An Encyclopedia of Social, Political, Cultural, and Economic History 5 vols. Armonk, N.Y.: Sharpe Reference 
Location: GELMAN Ref E162 .C68 2006
This encyclopedia explores the complete early history of what would become the United States.
Encyclopedia of American Cultural and Intellectual History. 3 vols. New York, Scribner, c2001
Location: GELMAN Ref E169.1 .E624 2001 2nd Floor
Gives essays that survey the character and variety of American thought and expression.
Encyclopedia of the American Revolutionary War 5 vols. Santa Barbara, Califl: ABC-CLIO, c2006
Online. This scholarly reference on the American Revolution covers the causes, course, and consequences of the war and the political, social, and military origins of the nation.
Encyclopedia of the United States in the Nineteenth Century.. 3 vols. New York, Charles Scribner's Sons, 2001
Location: GELMAN Ref E169.1 .E626 2001 2nd Floor
Provides substantive entries on the events, trends, movements, technologies, and cultural and social changes that shaped America in the 19th C.
Encyclopedia of the United States in the Twentieth Century. 4 vols. New York, Charles Scribner's Sons, c1996.
Location: GELMAN Ref E740.7 .E53 1996 2nd Floor
In-depth essays address the political, economic, social, cultural, and technological developments that marked the U.S. in the 20th C.
Oxford Bibliographies Online: Atlantic History
Online. Offers exclusive, authoritative research guides that combine the best features of an annotated bibliography and a high-level encyclopedia.
Oxford Encyclopedia of American Military and Diplomatic History Oxford University Press, 2013
Online. This multi-volume reference work offers both assess and analysis of the key episodes, issues and actors in the military and diplomatic history of the United States.
Oxford Encyclopedia of American Social History 2 vols. New York : Oxford University Press, c2012
Online. Entries in this encyclopedia synthesize the work done with new sources and methodologies to shift the focus of historical interest to the experiences of ordinary people, examining American history "from the bottom up."