NOAA's Office of Coast Survey, part of the National Ocean Service, produces nautical charts for the nation.
A nautical chart is one of the most fundamental tools available to the mariner. It's a graphic portrayal of the marine environment showing the nature and form of the coast, the general configuration of the sea bottom, including water depths, locations of dangers to navigation, locations and characteristics of human-made aids to navigation and other features useful to the mariner.
The nautical chart is essential for safe navigation. In conjunction with supplemental navigational aids, it is used by the mariner to lay out courses and navigate ships by the shortest and most economically safe route. Over 98 percent of the nation’s cargo is carried by waterborne transportation—and all of those ships rely on nautical charts to find their way.