Due to the post-Independence Day admission of Hawaii as the 50th U.S. state on August 21, 1959, the 50-star flag of the United States debuts in Philadelphia, almost ten and a half months later (see Flag Acts (United States)).

In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sovereignty with the federal government. Due to this shared sovereignty, Americans are citizens both of the federal republic and of the state in which they reside. State citizenship and residency are flexible, and no government approval is required to move between states, except for persons restricted by certain types of court orders.

August 21 is the 233rd day of the year in the Gregorian calendar; 132 days remain until the end of the year.

The national flag of the United States, often referred to as the American flag or the U.S. flag, consists of thirteen horizontal stripes, alternating red and white, with a blue rectangle in the canton bearing fifty small, white, five-pointed stars arranged in nine offset horizontal rows, where rows of six stars alternate with rows of five stars. The 50 stars on the flag represent the 50 U.S. states, and the 13 stripes represent the thirteen British colonies that won independence from Great Britain in the American Revolutionary War.

Philadelphia, colloquially referred to as Philly, is the most populous city in the U.S. state of Pennsylvania. It is the sixth-most populous city in the United States with a population of 1.6 million at the 2020 census, while the Philadelphia metropolitan area with 6.33 million residents is the nation's ninth-largest metropolitan area. Philadelphia is known for its culture, cuisine, and history, maintaining contemporary influence in business and industry, culture, sports, and music.