St. Louis, Iron Mountain and Southern Railway
|Locale||Missouri and Arkansas, United States|
|Dates of operation||1874–1917|
|Successor||Missouri Pacific Railroad|
|Track gauge||4 ft 8 1⁄2 in (1,435 mm) standard gauge|
It ran from St. Louis, Missouri, to Texarkana, Arkansas, as well as to southeast Missouri. The line was initially established to deliver iron ore from Iron Mountain, Missouri to St. Louis. The company was frequently referred to as the St. Louis Iron Mountain & Southern (StLIM&S) or shortened to simply the Iron Mountain Railway.
In 1883 the StLIM&S was acquired by Jay Gould, becoming part of a 9,547 miles (15,364 km) system. On May 12, 1917, it was formally merged into the Missouri Pacific Railroad, which in turn was merged into the Union Pacific Railroad in 1982.
The railroad is famous for giving its name to the Iron Mountain Baby, and the railroad is reported to have paid for the child's education.
The name has been resurrected by a modern short line railroad based in Jackson, Missouri. The St. Louis, Iron Mountain and Southern Railway operates a heritage railroad in Cape Girardeau County, Missouri.