American Memory – Cities & Towns – The free online Cities & Towns Maps collection from the Library of Congress includes a variety of maps for America's cities and towns, from panoramic or "birds-eye" maps, to maps that depict individual buildings.
Sanborn Fire Insurance Maps – These historical maps, originally created for assessing fire insurance liability in approximately 12,000 U.S. towns and cities between 1867 and the 21st century, offer a wonderful research tool for locating city-dwelling ancestors. These maps include, among other details, the outlines of each building and outbuilding, the location of windows and doors, street names, street and sidewalk widths, property boundaries, fire walls, natural features (rivers, canals, etc.), railroad corridors, building use, house and block number, and even the composition of construction materials used in each building. The Library of Congress offers a great Sanborn Fire Insurance Maps Online Checklist, a searchable database of pre-1981 Sanborn Fire Insurance Maps in the Library's collection, with links to over 6,000 online digitized map sheets (of 700,000+ available in the full collection). Digital Sanborn Maps 1867-1970 is also available as an online collection via subscribing libraries and other institutions. Check with your local library to see if they offer free access.
City Directory & Ward Maps – A wonderful resource for genealogists researching city-dwelling ancestors, historical city directories include not only the street address and occupation of each resident but also often contain street maps providing details on area streets and major topographical features (i.e. railroads, rivers). Many include descriptions of the city's political wards as well, which helps to determine which ward an ancestor might be living in at a particular time. Comparing a historical map from a city directory with a present-day map can reveal streets that no longer exist or have undergone name changes.
City-Specific Historical Map Collections – Don't overlook the value of city-specific historical and genealogical resources. Historical map collections can be found online for many major cities; try a search for your locality and "historical maps" in your favorite search engine for your locality of choice. Examples of online city-based historical map collections that you can find with this strategy include:
- Historic Pittsburgh - Five major Pittsburgh historical map collections include a warranty atlas of original land grants; G. M. Hopkins Company Maps, 1872-1940; and City of Pittsburgh Geodetic and Topographic Survey Maps, 1923-1961.
- San Francisco Districts & Wards – Election district and ward boundary descriptions with accompanying maps for the years 1852, 1860, 1870 and 1880.
- Brooklyn Genealogy – Maps – A free collection of online digitized city and neighborhood maps from 1675 into the 1900s.
In addition to utilizing historic city maps, another important piece of urban genealogy research is to stay on top of ever-changing geographical and political boundaries as these can affect where you should search for specific historical records. Search out state or city-level guides for help in understanding the complexities of metropolitan boundary and political jurisdiction changes.