USA's continental congress adopted 'Stars and Stripes' as its national flag on June 14,1777. The flag initially had 13 red stripes and a circle of 13 white stars on blue background.
Congress officially designated June 14 as Flag Day in 1949.
in 1960, Government changed the flag and the flag consequently had 13 horizontal stripes alternating red and white; in the canton, 50 white stars of alternating numbers of six and five per row on a blue field.