Anti-Masonic Party: History of the faction which later helped form the Whig Party.
Constitutional Union Party: Information on the party formed for the 1860 elections.
Encyclopedia Americana: Progressive Party: Information on parties using this name led by Teddy Roosevelt, Robert LaFollette and Henry Wallace successively.
Evolution of Political Parties: Stephen M. Merrill outlines the birth, evolution, and death of political parties in the United States from the colonial period to the Benjamin Harrison administration, including a brief glance at third parties. Searchable page images. [The North American Review]
Grolier Multimedia Encyclopedia: Progressive Party: Article for teens on the three twentieth-century parties that used this name.
Historical Election Results: Presidential election results from 1789 to the present.
Jensen's American Political History On-Line: Extensive political history links.
The History of American Political Parties: US political history resources.
The History of Political Parties: Guide to articles on the web about the different parties that rose and fell over time including the third parties that never 'made it.'
The Political Graveyard: The web site that tells where the dead politicians are buried.
Why Third Parties?: Whether their candidates win or not, America's third political parties are important and here's why. Article examines the history of third parties and their impact.