A colleague at Yale forwarded this great link, a guide to research composed by historian William Cronon.
It's well worth a careful look.
Curator of American and British History
U.S. History
Territorial Growth of the United States of America, 1783-1866
FEATURED RESOURCE Archive of Americana
The Archive of Americana is a collection of historical documents including America's Historic Newspapers, American Broadsides and Ephemera, Early American Imprints Series I and Early American Imprints Series II, and American State Papers.
