SC-21 was a research and development program started in 1994 intended to design land attack ships for the United States Navy. A wide variety of designs were created and extensively examined, including an arsenal ship with 500 cruise missiles. Eventually a "tumblehome" design of around 16,000 tons with two long-range guns and 128 missile tubes was selected as the DD-21, the Destroyer for the 21st century. The program ended in November 2001.

The Zumwalt-class destroyer is a class of three United States Navy guided-missile destroyers designed as multi-mission stealth ships with a focus on land attack. The class was designed with a primary role of naval gunfire support and secondary roles of surface warfare and anti-aircraft warfare. The class design emerged from the DD-21 "land attack destroyer" program as "DD(X)" and was intended to take the role of battleships in meeting a congressional mandate for naval fire support. The ship is designed around its two Advanced Gun Systems (AGS), turrets with 920 round magazines, and unique Long Range Land Attack Projectile (LRLAP) ammunition. LRLAP procurement was canceled, rendering the guns unusable, so the Navy re-purposed the ships for surface warfare. Starting in 2023, the Navy will remove the AGS from the ships and replace them with hypersonic missiles.