ArchiveGrid, a union catalog of archival collections, provides access to nearly a million collection descriptions and online archival finding aids of archival material from more than 2,500 libraries, museums, historical societies, and archives around the world. ArchiveGrid is an important destination for searching through historical documents, personal papers, and family histories. Users can obtain more information on many items in each of these collections, contact archives to arrange a visit to examine materials, and order copies.

Lehigh University Libraries is one of the participants and most of our archival holdings are represented in the ArchiveGrid.

National Union Catalog of Manuscript Collections

The mission of the NUCMC program is to provide and promote bibliographic access to the nation's documentary heritage. This mission is realized by NUCMC production of cataloging describing archival and manuscript collections held by eligible repositories located throughout the United States and its territories.

NARA The U.S. National Archives and Records Administration --  See the "Using National Archives" library guide by Science Librarian Brian Simboli for visiting the NARA and conducting a research there.

Library of Congress

Library and Archives Canada 

Archivo General de la Nacion (National Archives of Mexico)

The National Archives of the U.K.

The National Archives of France (Archives Nationales) 

Das Bundesarkiv (The National Archives of Germany)

Worldcat is a network of libraries.  Going to "Advanced Search" and limiting by format will point you to archival materials from many different types of repositories around the world.