Observed arrival · 2026-09-29

mapsnap: Sanborn maps, placed on today’s map

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Editorial interest 82/100 Selection signal · not a rating of the site

mapsnap automatically georeferences the Library of Congress’s Sanborn fire insurance maps and provides the resulting IIIF annotations for download and reuse.

Landing page captured for the 2026-09-29 issue.

For: Historical-map researchers and GIS users
Worth noticing: The v1.3 release lists 29,673 volumes and 341,093 placed sheets, downloadable by state or all at once.

Field notes

The page credits the Library of Congress Sanborn Maps Collection for sheet images and OpenStreetMap contributors for georeference annotations, which it says are under ODbL. The v1.3 data can be downloaded by state or as a complete set, and a Brooklyn 1939, volume 2 example opens in the Allmaps viewer. The project also links to its code on GitHub.

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