United States (World War Z)

The United States of America (USA), commonly referred to as the United States (U.S.) or America, is a federal republic consisting of 51 states.

Battle of Yonkers
The Battle of Yonkers was the United States' first large scale, official engagement of the Zombie War. It took place in Yonkers, New York, the largest city in Westchester County. The battle was an unmitigated catastrophe. Poor planning, impractical equipment and outdated tactics all played their part, and culminated into the 4 million-strong zombie horde overwhelming the military. Yonkers was abandoned, and public confidence was non-existent, and was one of the primary causes of the excesses of the Great Panic.

Destruction of Washington D.C.
The Battle for the Capital went just as well as the Battle of Yonkers. However, President Powell authorized the detonation of a low-yield nuclear device on the city. The zombies closest to ground zero were vaporized, however most of the horde had survived. This had shattered morale.