This is the coolest website in the world.
Before I read Joshua Jelly-Shapiro's "All over the Map" in the September issue of Harper's Magazine, I had never heard of David Rumsey. Rumsey is a former real estate developer who has over 150,000 maps in his San Francisco house, making it, according to Jelly-Shapiro, "one of the finest private collections in the world." But while the article is behind the Harper's paywall, the maps are just a click away from your perusal.
Rumsey has uploaded some 33,000 maps to his website, the David Rumsey Map Collection, where you could spend your entire life looking at a new historical map every day. You can browse the maps in brilliantly high resolution the old-fashioned way, or you can open a version of Google Earth that lays them over satellite imagery at scale. Using a slider to adjust the opacity of the map, you can move back and forth from cartography to satellite images, studying everything from urban development in Washington D.C. to the shifting course of the Mississippi to the accuracy and inaccuracy of the mapmakers of yore.
It's one of the most dangerous tools of procrastination we have ever seen, so bookmark the page for next week -- who knows where it could take you?
They're even embeddable, so here's a couple to start you off: first, the United States in 1804.
And New York City, 1846. Happy mapping!
Maps from the David Rumsey Map Collection.
Top image: screenshot of the David Rumsey Map Collection.