USS Mississippi (BB-23) was the lead ship of the Mississippi class originally built by the US Navy in 1904–1908. The class was built to a design smaller than other American battleships as the result of a limit on displacement imposed by Congress as part of an effort to constrain costs. The ships were armed with a main battery of four 12 in (305 mm), the standard for pre-dreadnought battleships of the time, but to secure that heavy primary armament, significant compromises in speed, secondary batteries, and armor protection were necessary to keep the ship within the prescribed displacement limit.

The Mississippi class of battleships comprised two ships which were authorized in the 1903 naval budget: Mississippi and Idaho; these were named for the 20th and 43rd states, respectively. These were the last pre-dreadnought battleships to be designed for the United States Navy, but not the last to be built, because one more ship of a prior design was completed later under the 1904 naval budget. While the quality and technology of the weaponry and armor were first-rate, these ships included a variety of main, intermediate, secondary, and tertiary gun sizes in a predreadnought configuration which became obsolete before the ships were completed.