20,000 historical maps through NYPL Digital Collections. These maps can be downloaded in high resolution to re-use in your own projects. Highlights of the collection includes maps of Mid-Atlantic North America from the 16th through 19th centuries, maps of the Austro-Hungarian Empire, and more than 1,000 historical maps of New York City.
The NYPL's Map Division offers a new tool called the Map Warper for overlaying historical maps on top of current maps. The Map Warper is similar in concept to using historical images as overlays on Google Earth. The difference is that Map Warper doesn't require you to install software on your computer. Learn more about the Map Warper in the video below.
Applications for Education
One of the ways that I've used historical maps in my classroom in the past is to have students evaluate the role of physical geography in the development of cities. I've also had students use historical maps to compare our current understanding of the world with that of cartographers of the 15th and 16th centuries.
H/T to Open Culture.