Much remains to be learned from exploring the mysteries of the deep. From mapping and describing the physical, biological, geological, chemical, and archaeological aspects of the ocean to understanding ocean dynamics, developing new technologies, and unlocking other secrets of the ocean, NOAA is working to increase our understanding of the ocean realm.

The ocean is the lifeblood of Earth, covering more than 70 percent of the planet's surface, driving weather, regulating temperature, and ultimately supporting all living organisms. Throughout history, the ocean has been a vital source of sustenance, transport, commerce, growth, and inspiration.

Yet for all of our reliance on the ocean, more than eighty percent of this vast, underwater realm remains unmapped, unobserved, and unexplored.

Given the high degree of difficulty and cost in exploring our ocean using underwater vehicles, researchers have long relied on technologies such as sonar to generate maps of the seafloor. Currently, less than ten percent of the global ocean is mapped using modern sonar technology. For the ocean and coastal waters of the United States, only about 35 percent has been mapped with modern methods.

NOAA’s Office of Ocean Exploration and Research is leading efforts to explore the ocean by supporting expeditions to investigate and document its unknown and little known regions. These expeditions are led by scientist-explorers equipped with the latest exploration tools.

Meanwhile, NOAA's Office of Coast Survey explores the ocean in a different way, employing hydrographic surveys to generate nautical charts. Since the mid-1830s, the U.S. Coast Survey (a NOAA predecessor agency) has been the nation’s nautical chartmaker. Today, Coast Survey is still responsible for creating and maintaining all charts of U.S. coastal waters, the Great Lakes, and waters surrounding U.S. territories.