To create his All Rivers map, Nelson Minar mined open source data from the National Hydrography Dataset. All images: Courtesy Nelson Minar

Minar's All Rivers map is an in-depth look at waterways in the 48 contiguous states.

He was inspired by Ben Fry's All Streets map, which similarly depicts all the roads in the U.S.

To determine how large the rivers would appear on the map, Minar extracted the Strahler number, a measure of how significant a creek is.

Places like Mississippi were thick with blue.

But even notoriously dry locations like Nevada and Southern California were covered in blue.

Though the waterways are dry most of the year, the creek beds are still defined.

Minar notes that to be a truly useful hydrography map, it should have information on river volume, size, seasonality, etc.