We've updated the Map Division's Google Earth index to digitized NYC map collections to include more than 2000 maps from 32 titles, organized chronologically and geographically (by borough), all published between 1852 and 1923. The map index (download .kmz file) requires installation of Google Earth on your computer. There are three recommended ways to search for maps using this tool.
1. Select a borough and vintage using the folders from the list on the left sidebar.
2. Double click the map to fly to your chosen location, then use the time slider at the top left of the map frame to narrow the chronological search scope.
3. Enter a street address in the "fly to" search box, then use the time slider. Once you've located a historical map coverage, scroll your mouse over the area and click. A popup window will allow you to access bibliographic information and a digital copy of the historical map.