A national flag is a flag that represents and symbolizes a given nation. It is flown by the government of that nation, but can also be flown by its citizens. A national flag is typically designed with specific meanings for its colours and symbols, which may also be used separately from the flag as a symbol of the nation.

The national flag of the United States, often referred to as the American flag or the U.S. flag, consists of thirteen equal horizontal stripes of red (top and bottom) alternating with white, with a blue rectangle in the canton, referred to as the union and bearing fifty small, white, five-pointed stars arranged in nine offset horizontal rows, where rows of six stars (top and bottom) alternate with rows of five stars.

national flag consisting of white stars (50 since July 4, 1960) on a blue canton with a field of 13 alternating stripes, 7 red and 6 white. The 50 stars stand for the 50 states of the union, and the 13 stripes stand for the original 13 states. The flag’s width-to-length ratio is 10 to 19.

The colours and designs of national flags usually are not arbitrarily selected but rather stem from the history, culture, or religion of the particular country. Many flags can be traced to a common origin, and such “flag families” are often linked both by common traditions and by geography.