50 stars in the American flag represent 50 states of the Unites states of America.
Thirteen horizontal stripes alternating red and white and 50 white stars of alternating numbers of six and five per row on a blue field – this resolution for flag was adopted today in 1777. It all started with just 13 stars but with time new stars were added to represent new additions to the Union.
It was based on the “Grand Union” flag, a banner carried by the Continental Army in 1776.
On June 14, 1877, the first Flag Day observance was held on the 100th anniversary of the adoption of the Stars and Stripes. In 1949 Congress officially designated June 14 as Flag Day, a national day of observance.