There are several stages of pagents that must be taken to reach the Miss USA pageant. The first is your local pageant (if in a larger city, this will be broken up into smaller pageants, then the city wide final). The winner of a city pageant will go onto the state pageant and finally onto the Miss USA pageant.
In order to become a contestant in the Miss USA pageant you must follow the requirements given by the Miss Universe Organization, such as height, weight, marital status, and physical attractiveness.
