The current United States flag has 50 stars, a design associated with the nation celebrated by America250.
Each star represents one state in the Union. The 50-star flag became official on July 4, 1960, after Hawaii joined the United States. Alaska had joined earlier in 1959, briefly producing a 49-star flag before the Hawaii-based design took effect.
The flag also has 13 horizontal stripes. Those stripes represent the thirteen colonies that declared independence from Great Britain. The 1777 Flag Resolution established the basic idea of thirteen stripes and thirteen stars, although it did not prescribe a particular arrangement for the stars.
A frequent mistake is to say that the stripes represent the current number of states. They do not: the stars change as states are admitted, while the stripes remain at 13 to honor the original colonies. Flag Day is observed on June 14, the anniversary of the 1777 resolution.