Which ocean borders the east coast of the United States?

The ocean bordering the east coast of the United States is the Atlantic Ocean.

The Atlantic lies between the Americas and Europe and Africa, and its western margin reaches the United States from Maine to Florida. This is why the region is commonly called the Atlantic Coast, Atlantic Seaboard, or East Coast. The coastline meets the Atlantic directly, while major tidal rivers such as the Delaware and Potomac connect inland areas to the ocean.

The Atlantic has been central to United States history. European colonization, immigration, naval warfare, trade, and the growth of port cities all depended heavily on access to its waters. Boston, New York, Baltimore, Charleston, and Miami are among the prominent cities associated with the American Atlantic coast.

A frequent mix-up is confusing the Atlantic Ocean with the Gulf of Mexico. The Gulf borders the southern United States, especially the Gulf Coast, but it is a marginal sea of the Atlantic system rather than the ocean directly bordering the eastern seaboard. The Pacific Ocean borders the opposite, western side of the country.