John Fletcher Darby
4th Mayor of St. Louis, Missouri
In office April 14, 1835 – October 31, 1837
Preceded by	John W. Johnson
Succeeded by	William Carr Lane
In office April 14, 1840 – April 13, 1841
Preceded by	William Carr Lane
Succeeded by	John D. Daggett
Member of the U.S. House of Representatives from Missouri's 1st district
In office March 4, 1851 – March 3, 1853
Preceded by	James B. Bowlin
Succeeded by	Thomas H. Benton
Member of the Missouri Senate
In office 1838
Personal details
Born	(1803-12-10)December 10, 1803 Person County, North Carolina
Died	May 11, 1882(1882-05-11) (aged 78) Pendleton, Missouri
Political party	Whig
Spouse	Mary Darby

John Fletcher Darby (December 10, 1803 – May 11, 1882) was a U.S. Representative from Missouri and the fourth mayor of St. Louis.

Darby was born in Person County, North Carolina. He moved with his father to Missouri in 1818, where he worked on a farm before moving to Frankfort, Kentucky, in 1825. Thereafter, Darby studied law and was admitted to the bar. He then returned to Missouri to practice in St. Louis. He was the Mayor of St. Louis from 1835 to 1837 and 1840 to 1841, between which he served as a member of the Missouri Senate, in 1838. During his time as mayor, Darby was very active in getting the first Missouri railroad convention held in St. Louis. Eventually, that led to the incorporation of two railroads in the state. Lafayette Park was built, becoming the first city park west of the Mississippi River.

He was elected as a Whig to the Thirty-second United States Congress (March 4, 1851, to March 3, 1853), after which he returned to St. Louis and became a banker. He died near Pendleton, Missouri, on May 11, 1882, and his remains are interred at Calvary Cemetery in St. Louis.