Editing Sanborn maps

{{Short description|Detailed maps of cities and towns in the United States}}
{{Use American English|date = February 2020}}
{{Use mdy dates|date = February 2020}}
{{Infobox product
| title            = Sanborn maps
| image            = Sanborn Boston 1867 sheet 1a.gif
| image_size       = 
| caption          = Sanborn map of Boston from 1867
| type             = [[City map]]
| inventor         = [[Daniel Alfred Sanborn]]
| inception        = {{start date|1866}}
| manufacturer     = The Sanborn Map Company
| available        = Available
| current supplier = LightBox
| last production  = 
| models           = 
| website          = https://edrnet.com/prods/sanborn-maps/
| notes            = 
}}
'''Sanborn maps''' are detailed maps of U.S. cities and towns in the 19th and 20th centuries. Originally published by '''The Sanborn Map Company''' (Sanborn), the maps were created to allow [[fire insurance]] companies to assess their total liability in urbanized areas of the United States.  Since they contain detailed information about properties and individual buildings in approximately 12,000 U.S. cities and towns, Sanborn maps are valuable for documenting changes in the [[built environment]] of American cities over many decades.<ref name="keister1993">{{cite journal | last=Keister | first=Kim | title=Charts of Change | journal=Historic Preservation | volume=45  | issue=3 | pages=42–49 |date=May–June 1993 | quote=Stated simply, the Sanborn maps survive as a guide to American urbanization that is unrivaled by other cartography and, for that matter, by few documentary resources of any kind. }}</ref>

Sanborn held a monopoly over fire insurance maps for the majority of the 20th century, but the business declined as US insurance companies stopped using maps for underwriting in the 1960s. The last Sanborn fire maps were published on [[Microform|microfilm]] in 1977, but old Sanborn maps remain useful for historical research into urban geography.  The license for the maps was acquired by land data company Environmental Data Resources (EDR), and EDR was acquired in 2019 by real estate services company LightBox.<ref name=loc1>{{cite web|url=https://www.loc.gov/loc/lcib/9712/map.html |title=Library Announces Digital Map Project |website=Library of Congress|date=1997-12-01 |accessdate=2020-10-30}}</ref><ref name=real1>{{cite web|url=https://therealdeal.com/2019/05/13/silver-lake-backed-startup-lightbox-makes-even-more-re-tech-acquisition-noise/ |title=Silver Lake-backed startup Lightbox makes even more RE Tech acquisition noise |website=The Real Deal|date=2019-05-13 |accessdate=2020-10-30}}</ref>

==Description==

The Sanborn maps themselves are large-scale [[lithograph]]ed street plans at a scale of 50 feet to one inch (1:600) on {{convert|21|by|25|in|cm}} sheets of paper.  The maps were published in volumes, bound and then updated until the subsequent volume was produced.  Larger cities would be covered by multiple volumes of maps.  Between editions of published volumes, map updates were sent out as correction slips.  Sanborn employees, called "pasters" or "correctors", would visit subscribers' offices to paste the slips on top of the old maps.<ref name="loc">{{cite web|title=Introduction to the Collection – Sanborn Maps|url=https://www.loc.gov/collections/sanborn-maps/articles-and-essays/introduction-to-the-collection/|website=The Library of Congress|accessdate=5 January 2017}}</ref><ref name="buffett1960">{{cite web|last1=Buffett|first1=Warren|title=Letter from Warren Buffett to Partners, 1960|url=https://www.gurufocus.com/news/7227/warren-buffett-partnership-letter-of-1960}}</ref><ref name="ristow1968"/>

The map volumes contain an enormous amount of information.  They are organized as follows: a decorative title page; an index of streets and addresses; a ‘specials’ index with the names of churches, schools, businesses etc.; and a master index indicating the entirety of the mapped area and the sheet numbers for each large-scale map (usually depicting four to six blocks); and general information such as population, economy and prevailing wind direction.<ref name="loc"/>

The maps include outlines of each building and outbuilding; the location of windows and doors; street names; street and sidewalk widths; property boundaries; fire walls; natural features ([[river]]s, [[canal]]s, etc.); railroad corridors; building use (sometimes even particular room uses); house and block number; as well as the composition of [[building material]]s including the framing, flooring, and roofing materials; the strength of the local fire department; indications of sprinkler systems; locations of [[fire hydrant]]s; location of water and gas mains; and even the names of most public buildings, churches and businesses.<ref name="loc"/>

Unique information includes the location of the homes of prominent individuals, brothels, and more ephemeral buildings including outhouses and stables.

== Insurance underwriting ==

At the outset of the [[fire insurance]] industry, [[Underwriting#Insurance underwriting|underwriters]] visited every property that was under consideration for coverage.<ref name="ristow1968">{{cite journal|last1=Ristow|first1=Walter W.|title=United States Fire Insurance and Underwriters Maps: 1852–1968|journal=The Quarterly Journal of the Library of Congress|date=1968|volume=25|issue=3|pages=194–218|jstor=29781319}}</ref>  As insurance companies increased their service areas, it was no longer practical to send people to every insurable property to assess the risk.  The Sanborn maps allowed them to underwrite properties from the office, pooling the cost with other insurance companies that also subscribed to the maps.  It was said that at one time, insurance companies and their agents “relied upon them with almost blind faith”.<ref name="keister1993"/>

The maps were utilized by insurance companies to determine the potential risk of a particular building, taking into account all of the information included on the map: building material, proximity to other buildings and [[fire department]]s, the location of gas lines, etc.  The decision as to how much, if any, insurance would be offered to a customer was often determined solely through the use of a Sanborn map.  The maps also allowed insurance companies to visualize their exposure in their coverage areas; when an agent sold a policy, he could color in the corresponding building on the map.

== History ==

[[File:Lagoon Map 1911.JPEG|left|thumb|1911 Sanborn map showing Lagoon Amusement Park in [[Farmington, Utah]]]]

In the late 18th century, insurance companies in London began to create detailed maps to give underwriters the information they needed to assess fire risk.  The practice was adopted by American insurance companies in the mid-19th century.<ref name="loc"/>  Demand for fire insurance mapping grew rapidly after the end of the [[American Civil War|Civil War]].  Factors such as the [[Homestead Act]], [[railroad]] construction, the [[Second Industrial Revolution]] and massive [[immigration to the United States]] all fostered huge population growths, urbanization, and heightened demand for mapping.

[[Daniel Alfred Sanborn]], a civil engineer and surveyor, began working on fire insurance maps in 1866. That year, he was contracted by the [[Aetna|Aetna Insurance Company]] to prepare maps of areas in [[Tennessee]]. About the same time, he developed similar maps of [[Boston]], published as ''Insurance Map of Boston,'' Volume 1, 1867. Seeing a lucrative market for this type of map, he established the D. A. Sanborn National Insurance Diagram Bureau in New York City to publish the Boston atlas and develop and sell maps of additional areas.<ref name="loc"/>

Within several decades, the company became the largest and most successful American map company. This growth came about through savvy management and the buyout of competing firms. In 1889 Sanborn acquired Perris and Browne, an older firm, and can by virtue of this expansion date its origins to 1852. The firm name established by Sanborn in 1867 was changed in 1876 when the firm was incorporated under the name Sanborn Map and Publishing Company, which then became the Sanborn-Perris Map Company, Ltd. until 1902, when the name was shortened to the Sanborn Map Company.<ref>{{citation|title=Introduction to the Sanborn Map Collection|last=Ristow|first=Walter W.|url=https://www.loc.gov/rr/geogmap/sanborn/san4a1.html}}. Regarding Sanborn's acquisition of Perris, Ristow gives the year as 1899, but on the published maps the name changed from 1889 to 1890. See for example the [[c:File:Sanborn Fire Insurance Map from San Francisco, San Francisco County, California. LOC sanborn00813_005-2.jpg|title page]] from: ''Insurance Maps of San Francisco, California''. Volume 3. (New York: Sanborn Map & Publishing Company Limited, 1889) and the [[c:File:Sanborn Manhattan V. 4 title page publ. 1890.jpg|title page]] from: ''Insurance Maps of the City of New York Surveyed and Published by Sanborn–Perris Map Co., Limited''. Volume 4. (New York: 1890).</ref>

In 1916, Sanborn purchased its last major competitor, the E. Hexamer & Sons of Philadelphia, and became a [[monopoly]].  Company headquarters moved to 629 Fifth Avenue in northern [[Pelham, New York]], but there were also regional offices in [[San Francisco]], [[Chicago]], and [[Atlanta]]. The Sanborn Company sent out legions of surveyors to map building footprints in all major urbanized areas, along with building details related to fire risk.  At its peak in the 1920s, the company employed about 700 people, including about 300 field surveyors and 400 cartographers, printers, managers, salesmen, and support staff.  Areas under intensive development were surveyed every six months.<ref name="ristow1968"/>
[[File:"MARKET STREET CABLE R. W. CO." in 1889 map detail, Sanborn Fire Insurance Map from San Francisco, San Francisco County, California. LOC sanborn00813 005-9 (cropped).jpg|thumb|"MARKET STREET CABLE R. W. CO." in 1889 map detail from Sanborn Fire Insurance Map of [[San Francisco]], California]]
Sanborn's monopoly was resented by some insurance companies for its high cost.  The Underwriter's Association of the Pacific complained that an "Eastern monopoly" was giving service that was "very slow, expensive, and generally unsatisfactory."  In the 1910s, the National Board of Fire Underwriters investigated the possibility of creating its own maps.  However, many insurance companies opposed the proposal, citing the "very large expenditure" required and their satisfaction with Sanborn's "commendably satisfactory" service.  Instead, the NBFU Map Committee took an active role in Sanborn's operations.  In 1922, Sanborn agreed to add a member of the Map Committee to its [[Board of Directors]], and a second seat was added by 1927.  However, the onset of the [[Great Depression]] greatly curtailed construction activity in the United States.  By 1936, Sanborn had reduced its publishing output from 60 to 20 volumes per year, a pace that would take over 50 years to update the entire map collection.<ref name="ristow1968"/>

=== Decline of insurance business ===

In the 1950s, insurance companies began to use an alternative form of [[underwriting]] known as ''line carding''.<ref name="loc"/><ref name="buffett1960"/>  Line carding had been used for decades to underwrite properties that were not covered by fire maps.<ref name="alabama1921">{{cite book|title=Annual Report of the Commissioner of Insurance of the State of Alabama for the Year Ending December 31, 1921|date=1922|publisher=Brown Printing Company|location=Montgomery, Alabama|page=44|quote=Maps are kept of business in the downtown district and proper care is exercised in considering block lines and conflagration hazard.  They propose to institute a line card system to properly care for lines not shown on maps.}}</ref>  Each insured property was listed on a single card, and no map was kept.  Corporate mergers also reduced the need for Sanborn Maps, since the consolidated company only needed to buy one set of maps.  As insurance companies increased in size, they could withstand larger disasters and no longer needed to use insurance maps to reduce their concentration of risk.  Companies also cited "modern building construction, better [[building code|building fire codes]], and improved fire protection methods for the decline in importance of fire insurance maps."<ref name="ristow1968"/>

From the late 1930s to the late 1950s, Sanborn's annual profit fell from $500,000 to just $100,000.  About thirty insurance companies accounted for most of the company's sales.  However, its monopoly over insurance mapping had allowed it to earn substantial profits over the decades.  These profits were invested in a portfolio of stocks and bonds.  By 1958, the stock was selling for $45 per share, but the investment portfolio was worth $65 per share.  This attracted the attention of the young [[Warren Buffett]], who pressured the company to distribute the investment portfolio to shareholders.<ref name="buffett1960"/>
[[File:"New Orleans Brewing Association" Brewery in 1896, Sanborn Fire Insurance Map from New Orleans, Orleans Parish, Louisiana. LOC sanborn03376 007-3 (cropped).jpg|left|thumb|"New Orleans Brewing Association" Brewery in 1896 from Sanborn Fire Insurance Map of New Orleans]]
Buffett eventually purchased 23% of the company's outstanding shares as an [[activist investor]], representing 35% of his investment partnership's total [[assets under management]].  Allied with other dissatisfied shareholders, Buffett could count on the votes of at least 44% of the shares in a [[proxy fight]].  The Board agreed to [[Share repurchase|buy back]] shares from any shareholder at fair value, paying with a portion of its investment portfolio.  72% of the outstanding shares were turned in.<ref name="buffett1960"/>  In just two years, Buffett had secured a 50% return on his investment.<ref>{{cite book|last1=Lowenstein|first1=Roger|title=Buffett: The Making of an American Capitalist|date=1995|publisher=Random House Trade Paperbacks|location=New York|isbn=9780804150606|pages=65–66|edition=2008 Trade Paperback}}</ref>

With the decline of its insurance business, Sanborn could no longer afford to maintain its army of surveyors.  However, the company continued to sell its maps and perform some updates. Government sales began to play a larger role, especially the [[United States Census Bureau|Census Bureau]] and municipal planning agencies.  Sanborn printed its last catalog in 1950, created its last new map in 1961, and issued its last update in 1977.<ref name="loc"/>

In 1996, the license for the maps was acquired by land data company Environmental Data Resources (EDR).<ref name=loc1/>{{citation needed|date=October 2020}}  In 2019, EDR was acquired by real estate services company LightBox.<ref name=real1/>

Over time, Sanborn diversified into other mapping activities, and as of 2020 is a geospatial specialist and holder of electronic GIS assets and systems, though the fire insurance business continues as a niche department. Corporate headquarters are in Colorado.<ref>{{Cite web|url = http://www.sanborn.com/|title = Corporate home page|accessdate = 2015-05-14|website = Total Geospatial Solutions|publisher = Sanborn}}</ref>

{{Anchor|Modern uses}}

==  Modern uses of fire insurance maps ==
{{unreferenced section|date=October 2020}}
[[File:LouisianaSugarExchangeBlockSanborne1908.jpg|right|thumb|Early 20th century Sanborn map showing a (since demolished) block of [[New Orleans]]]]
Sanborn maps are found primarily in the archives and special collections of [[town hall]]s and public and university libraries, and remain a resource for people in many different fields.  The maps facilitate historical research through the study of urban growth and decline patterns, and for research into the evolution of specific buildings, sites and districts.  Genealogists use the maps to locate the residences and workplaces of ancestors.  [[Urban planning|Planners]] use the maps to study historic urban planning designs.  [[Historic preservation]]ists use the maps to understand the significance and historical evolution of buildings, including their historic uses and building materials in conservation and rehabilitation efforts.  [[Demographer]]s and urban geographers use them to study patterns of growth and migration of populations. Environmental scientists also use the maps for historical analysis of properties, as the maps often showed the locations of gas stations, drycleaners, and other potential sources of soil and groundwater contamination.

Historic Sanborn maps are available through public or university libraries, including the [[Library of Congress]], and from the copyright owners, Environmental Data Resources (EDR), a division of LightBox.<ref>{{Cite web |title=Sanborn Fire Insurance Maps Now Online |url=https://www.loc.gov/item/prn-17-074/sanborn-fire-insurance-maps-now-online/2017-05-25/ |access-date=2025-01-05 |website=Library of Congress, Washington, D.C. 20540 USA}}</ref><ref>{{Cite web |title=EDR® |url=https://www.lightboxre.com/product/edr-environmental-data-resources/ |access-date=2025-01-05 |website=LightBox |language=en-US}}</ref>

==See also==
*[[Walter Ristow]]

==References==
{{Reflist}}

==Further reading==
* {{cite book | last=Oswald | first=Diane L. | title=Fire Insurance Maps: Their History and Applications | location=College Station, Texas | publisher=Lacewing Press | year=1997 }}
* {{cite book | last=Ristow | first=Walter | title=American Maps and Mapmakers | location=Detroit | publisher=Wayne State University Press| year=1985 }}

==External links==
{{Commons category|Sanborn maps}}
*[http://www.sanborn.com/ Sanborn Map Company]
* [https://www.loc.gov/rr/geogmap/sanborn/san4a1.html Introduction to the Sanborn Map Collection]. [[Library of Congress]].
* {{cite web | author=Tom Gates | title=Information About Digital Sanborn Maps  | publisher=Kent State University, Libraries & Media Services | url=http://dmc.ohiolink.edu/help/sanborngates.html | year=2001| accessdate=1 July 2011}}
* {{cite web | author=Chris Nehls| title=Sanborn Fire Insurance Maps, A Brief History | url=http://fisher.lib.virginia.edu/collections/maps/sanborn/about.html  | publisher=Geostat Center and Department of History, University of Virginia | year=2003 | accessdate=1 July 2011}}
* {{cite web | title=Sanborn Fire Insurance Maps | url=http://cluster3.lib.berkeley.edu/EART/snb-intr.html | accessdate=20 March 2014}}
* {{cite web | title=Historical Atlases Rescued from the Trash Could be a Boon to Historians | url=https://www.nationalgeographic.com/adventure/article/historical-atlas-maps-american-west| archive-url=https://web.archive.org/web/20210515004338/https://www.nationalgeographic.com/adventure/article/historical-atlas-maps-american-west| url-status=dead| archive-date=May 15, 2021| accessdate=23 October 2023}}
* {{cite web | title=Sanborn | publisher=Digital Collections, Berkeley Library, University of California | url=https://digicoll.lib.berkeley.edu/search?ln=en&p=sanborn&f=&action_search=Search&rm=&sf=&so=d&rg=10&c=Digital+Collections&of=hb&fti=0&fti=0| accessdate=23 October 2023}}

===Digital map collections===
*[http://sanborn.umi.com/ ProQuest Digital Sanborn Maps, 1867–1970] — pay site (free from some public and academic libraries)
*[http://edrnet.com/prods/sanborn-maps/ Sanborn Maps, Environmental Data Resources] — pay site
*[https://www.loc.gov/rr/geogmap/sanborn/ Sanborn Maps from over 15 states] — [[Library of Congress]]
*[http://alabamamaps.ua.edu/historicalmaps/FireInsurance/1_County%20Index.html Sanborn Maps of Alabama, 1884–1950] — [[University of Alabama]]
*[http://www.sfgenealogy.com/sf/sanborn/sanborn.htm Sanborn Maps of San Francisco, California, 1900] — SF Genealogy
*[http://www.davidrumsey.com/blog/2011/6/27/pre-earthquake-san-francisco-1905-sanborn-insurance-atlas Sanborn Maps of San Francisco, California, 1905] — [[David Rumsey]]
*[http://www.sjpl.org/tags/sanborn-maps Sanborn Maps of San Jose, California] – [[San Jose Public Library]] – Digital Sanborn Fire Maps of San Jose available to library card holders
*[http://libcudl.colorado.edu:8180/luna/servlet/UCBOULDERCB1~21~21 Sanborn Maps of Colorado, 1883–1922] — [[University of Colorado]] Digital Library
*[http://ufdc.ufl.edu/sanborn Sanborn Maps of Florida, 1860–1923] — [[University of Florida Library West|University of Florida Library]]
*[http://dlg.galileo.usg.edu/sanborn/?Welcome Sanborn Maps of Georgia, 1884–1922] — Digital Library of Georgia
*[https://digital.library.illinois.edu/collections/6ff64b00-072d-0130-c5bb-0019b9e633c5-2 Sanborn Fire Insurance Maps of Illinois] — [[University of Illinois Urbana-Champaign|University of Illinois at Urbana-Champaign]], Map Library
*[http://www.ulib.iupui.edu/digitalscholarship/collections/sanbornjp2 Sanborn Maps of Indianapolis, Indiana, 1887–1941] — [[IUPUI University Library]]
*[http://dmr.bsu.edu/collection.php?CISOROOT=/SanbrnMps Sanborn Maps of Muncie, Indiana, 1883–1911] — [[Ball State University]] Library
*[https://digital.lib.ku.edu/ku-sanborn/root Sanborn Maps of Kansas, 1883–1922] — [[University of Kansas Libraries]]
*[http://kdl.kyvl.org/cgi/i/image/image-idx?page=index;c=beasanic;g=kdlmaps Sanborn Maps of Kentucky, 1884–1922] — Kentuckiana Digital Library
*[http://davidrumsey.com/northamericanatlases.html Sanborn Maps of Frankfort, Kentucky, 1907] — David Rumsey
*[http://davidrumsey.com/northamericanatlases.html Sanborn Maps of Hallowell, Maine, 1890] — David Rumsey
*[http://digitalcommons.library.umaine.edu/me_sanbornmaps/ Sanborn Maps of Maine] – [[University of Maine]] Fogler Library, Orono
*[http://mulibraries.missouri.edu/specialcollections/sanborn.htm Sanborn Maps of Missouri, 1883–1951] — [[University of Missouri]]
*[http://digital.wustl.edu/unrealcity/ Sanborn Maps of St. Louis, Missouri, 1870–1904] — [[Washington University in St. Louis]]
*[http://www.delamare.unr.edu/Maps/digitalcollections/nvmaps/sanborns/ Sanborn Maps of Nevada, 1879–1923] — [[University of Nevada, Reno]]
*[http://libweb5.princeton.edu/visual_materials/maps/sanborn/sanborn-web.htm Sanborn Maps of New Jersey, 1884–1950] — [[Princeton University Library]]
*[http://www.dartmouth.edu/~library/digital/collections/maps/sanbornmaps/ Sanborn Maps of New Hampshire, 1880s–1940s] — [[Dartmouth College]] Library
*[http://digitalgallery.nypl.org/nypldigital/dgtitle_tree.cfm?title_id=1926663&level=2&tword= Insurance Maps of New York] — [[New York Public Library]]
*[http://www.lib.unc.edu/dc/ncmaps/sanborn.html Sanborn Maps of North Carolina, 1884–1922] — [[University of North Carolina at Chapel Hill]]
*[http://virtuallibrary.cincinnatilibrary.org/virtuallibrary/vl_Maps.aspx Sanborn Maps of Cincinnati, Ohio] — The Public Library of Cincinnati and Hamilton County
*[http://www.toledosattic.org/details.asp?did=65 Sanborn Maps of Toledo, Ohio, 1902] — Toledo's Attic
*[http://www.libraries.psu.edu/psul/digital/sanborn.html Sanborn Maps of Pennsylvania, 1884–1958] — [[Pennsylvania State University Libraries]]
*[http://www.lib.utexas.edu/maps/sanborn/texas.html Sanborn Maps of Texas, 1877–1922] — University of Texas Libraries
*[http://www.sc.edu/library/digital/collections/sanborn.html Sanborn Maps of South Carolina, 1884–1960] — [[University of South Carolina Libraries|University of South Carolina Library]]
* [https://collections.lib.utah.edu/search?q=uum_sfim/ Sanborn Fire Insurance Maps] at [https://collections.lib.utah.edu/ University of Utah Digital Library], [https://lib.utah.edu/collections/special-collections/ Marriott Library Special Collections]
*[https://wisconsinhistory.org/Records/Article/CS3350 Sanborn Fire Insurance Maps of Wisconsin Communities] – [[Wisconsin Historical Society]]
*[https://collections.lib.uwm.edu/digital/collection/agdm/search/searchterm/kenosha%20(wis.)%20--%20maps!sanborn/field/subjec!all/mode/exact!all/conn/and!all/order/nosort/ad/asc Sanborn Maps of Kenosha, Wisconsin, 1918] — [[University of Wisconsin–Milwaukee|UW Milwaukee]], AGS Library
*[https://uwm.edu/lib-collections/sanborn/ Sanborn Maps of Milwaukee, Wisconsin, 1894 and 1910] — UW Milwaukee, AGS Library

[[Category:Urban planning in the United States]]
[[Category:Map companies of the United States]]