The ProQuest Collection of Sanborn Maps consists of "more than 660,000 large-scale maps of more than 12,000 American towns and cities." Users can manipulate the maps by magnifying and zooming in on specific areas.
This online collection is accessible to University of Michigan faculty, staff and students only.
You can purchase current Sanborn Maps though the Sanborn website.
Detroit Public Library
The Detroit Public Library houses Sanborn fire insurance maps for Detroit and other Michigan cities. For more information about available holdings, contact the Burton Historical Collection, which is located at the Main Library.
Center for Research Libraries
The Center for Research Libraries holds microfilm copies of all Sanborn fire insurance maps indexed in Fire Insurance Plans in the Library of Congress: A Checklist (Clark Library Z 6026 .I7 U541). They may be borrowed by UM affiliates through MLibrary Interlibrary Loan. On your request, please indicate the entry number, city name, and dates of the maps, and volume numbers from this publication.