The Delaware-class battleships of the United States Navy were the second class of American dreadnoughts. With this class, the 16,000 long tons (16,257 t) limit imposed on capital ships by the United States Congress was waived, which allowed designers at the Navy's Bureau of Construction and Repair to correct what they considered flaws in the preceding South Carolina class and produce ships not only more powerful but also more effective and rounded overall. Launched in 1909, these ships became the first in US naval history to exceed 20,000 long tons (20,321 t).

The dreadnought was the predominant type of battleship in the early 20th century. The first of the kind, the Royal Navy's HMS Dreadnought, had such an effect when launched in 1906 that similar battleships built after her were referred to as "dreadnoughts", and earlier battleships became known as pre-dreadnoughts. Her design had two revolutionary features: an "all-big-gun" armament scheme, with an unprecedented number of heavy-calibre guns, and steam turbine propulsion. As dreadnoughts became a crucial symbol of national power, the arrival of these new warships renewed the naval arms race between the United Kingdom and Germany. Dreadnought races sprang up around the world, including in South America, lasting up to the beginning of World War I. Successive designs increased rapidly in size and made use of improvements in armament, armour, and propulsion throughout the dreadnought era. Within five years, new battleships outclassed Dreadnought herself. These more powerful vessels were known as "super-dreadnoughts". Most of the original dreadnoughts were scrapped after the end of World War I under the terms of the Washington Naval Treaty, but many of the newer super-dreadnoughts continued serving throughout World War II.