I found this tool six years ago and meant to post it but forgot until now. Fortunately it still works and is still pretty cool. You can click anywhere in the United States and trace the path of a raindrop to the ocean. I chose a random point northwest of White River City in western Colorado.
River Runner is a tool from Sam Learner, a graphic journalist from the Financial Times. After it loads, you will get a fly through video tracing the raindrop's path. Here it is flowing down the Green River after passing through "Unnamed River" then Crooked Wash and then the White River. The red on the full USA map marks where you are at any given moment in the fly through.Here is the river as it approaches the Grand Canyon,
and here it is in the agricultural landscape along the Arizona-California border.Unfortunately since this river goes into Mexico before flowing into the sea, the path is detained at the border (this is no longer true see update below). To see an example of a river's mouth here is the Mississippi flowing into the Gulf of Mexico.
Don't expect a precise level of detail. I clicked at my house and it picked a point about a mile away where the flow to the nearest river is a bit different from where I am. It also got the name of a nearby lake wrong. Go here to see your local journey.UPDATE: River Runner is now a global phenomenon! You can now cross borders and go anywhere!