1846 - 1853
The flag of the United States of America had a varied number of stars for the period from 1845 to 1853.
In 1845 a 27th star had been added, and that flag with its diamond-pattern of stars was unaltered only until 1846. In 1846, a 28th star was added, causing the stars to be arranged in a staggered pattern until 1847.
From 1847 through 1848, there were 29 stars in a diamond pattern, followed by a 30th star which was displayed from 1848 to 1851. From 1851 through 1858, a windblown pattern of stars displayed 31 stars in all.