The New Mexico class was a class of three super-dreadnought battleships built for the United States Navy in the late 1910s. The class comprised three ships: New Mexico, the lead ship, Mississippi, and Idaho. Part of the standard series, they were in most respects copies of the Pennsylvania-class battleships that immediately preceded them, carrying over the same main battery arrangement of twelve 14-inch (356 mm) guns, but now increased to 50-caliber. They incorporated several other improvements, including a better arrangement of the secondary battery that increased its usability, a clipper bow that improved seakeeping, and an experimental turbo-electric propulsion system adopted on New Mexico. Like the other standard-type battleships, they had a top speed of 21 knots that allowed the fleet to operate as a tactically homogeneous unit.