How many states were in the US in 1831?

27 states. Florida was the 27th state to join in 1845 during President John Tyler's term.

See also the 27 Star Flag (1845-1846) . In 1845, one star was added, representing Florida, bringing the total number of stars to 27. There were thriteen stripes representing the original 13 colonies. Rick Wyatt, 5 April 1998.