Sanborn Fire Insurance Maps

Sanborn Fire Insurance Maps are a valuable resource for genealogical research. The Genealogy Insider blog from Family Tree Magazine's Diane Haddad provides a useful summary on how to use these maps.
http://blog.familytreemagazine.com/insider/2009/11/10/CincinnatiLib...

The downloadable versions being made available on the Public Library of Cincinnati and Hamilton County's Virtual Library are full color pdfs:
http://virtuallibrary.cincinnatilibrary.org/VirtualLibrary/vl_Maps....