Sunken territories

Sunken territories (also called underwater territories) refers to any parts of the contiguous United States that became submerged in the ocean when the ice caps melted. This has resulted in the loss of:
 * The entire states of Delaware, Connecticut, and Rhode Island
 * The vast majority of Florida, New Jersey, New Hampshire, Massachusetts, and Maine
 * A large portion of the eastern and Gulf coastline
 * Includes major cities like New York, Philadelphia, New Orleans, and Houston
 * A large portion of Mississippi, Louisiana, and Arkansas (now called the Mississippi Sea )
 * A large portion of Alabama (now called the Southern Great Lakes)
 * The entire Central Valley of California (now called Lake Sacramento )
 * The entirety of Cuba and the Bahamas

Allegedly, most other nations are not affected by this, as they made an effort to build flood walls and rebuild Antarctica. Nonetheless, people living in the affected areas have relocated and their cultures have persisted.