The 20 Star Flag 1818
Realizing that the addition of a new star and new stripe for each new State was impractical, Congress passed the Flag Act of 1818 which returned the flag design to 13 stripes and specified 20 stars for the 20 states.
This Flag became the Official United States Flag on April 13th, 1818.
(16th) Tennessee - June 1, 1796
(17th) Ohio - March 1, 1803
(18th) Louisiana - April 30, 1812
(19th) Indiana - December 11, 1816
(20th) Mississippi - December 10, 1817
Five stars were added and it was the official flag for just one year. The only President to serve under this flag was James Monroe (1817-1825).