The United States Navy, with its 300 warships, was the world's third largest by 1914. These warships were used to protect merchant and troopships across the Atlantic.

Some warships were also sent to the Mediterranean but most remained on the Atlantic seaboard of the USA.

The US Navy's most serious wartime losses were the cruiser San Diego sunk by mines from a U-boat off New York, and two destroyers lost on anti-submarine work in European waters.