Trace Any U.S. Waterway Upstream, Downstream, Sidestream

Remember this map of all the waterways in the U.S. from earlier this summer? Now there’s something even more fun: An interactive app that lets you not only see the waterways, but trace them to their source (or to their end, if it suits you better).

Streamer, a visualization from the National Atlas, shows almost all the streams in the U.S., or at least the ones large enough to see at a one to 1 million scale, meaning each inch of map corresponds to about 15.8 miles of land.

It gives you a look at how far water travels from some sources, and how short a distance another nearby waterway might stretch. There’s something especially satisfying about clicking a stream that dumps into a million different veins of water, or shoots its way across multiple states to empty into the ocean. Case in point: Hitting the coronary artery of American waterways, the Mississippi River, illuminates connections over the entirety of the middle of the country:

An Upstream Trace Of The Mississippi River

Or here’s a zoom-in of a more localized upstream search from my hometown in dry Southern California:

California Water

There’s an option to toggle between a satellite map and white terrain map as your base, over which the blue lines of creeks and rivers are drawn. The terrain map is brighter so a bit easier to read, but the satellite option gives you a better sense of the divides between desert, mountains and forests.

It’s a little bit wonky (sometimes you have to hit “clear map” before clicking from one stream to another, for example, and it’s super intuitive to navigate. Green lines delineate between regions–the Upper Mississippi, the Texas Gulf, etc.–which isn’t always easy to tell from a zoomed-in perspective. You have to zoom into select waterways, though, and I spent a lot of time mindlessly clicking until it grabbed ahold of something to trace.

Still. Waterways! They connect us all. Play with it here.