Southern Pacific system

Southern Pacific Transportation Company

SP system map (before the 1988 DRGW merger)
Reporting mark	SP
Locale	Arizona, Arkansas, California, Colorado, Illinois, Kansas, Louisiana, Missouri, Nevada, New Mexico, Oklahoma, Oregon, Tennessee, Texas, Utah
Dates of operation	1865–1996
Successor	Union Pacific
Track gauge	4 ft 8 1⁄2 in (1,435 mm) standard gauge with some 3 ft (914 mm) gauge branches
Headquarters	San Francisco, California

The Southern Pacific Transportation Company (reporting mark SP), earlier Southern Pacific Railroad and Southern Pacific Company, and usually called the Southern Pacific or (from the railroad's initials) Espee, was an American Class I railroad. It was absorbed in 1988 by the company that controlled the Denver and Rio Grande Western Railroad and eight years later became part of the Union Pacific Railroad.

The railroad was founded as a land holding company in 1865, later acquiring the Central Pacific Railroad by lease. By 1900 the Southern Pacific Company was a major railroad system incorporating many smaller companies, such as the Texas and New Orleans Railroad and Morgan's Louisiana and Texas Railroad. It extended from New Orleans through Texas to El Paso, across New Mexico and through Tucson, to Los Angeles, through most of California, including San Francisco and Sacramento. Central Pacific lines extended east across Nevada to Ogden, Utah, and reached north through Oregon to Portland. Other subsidiaries eventually included the St. Louis Southwestern Railway (Cotton Belt), the Northwestern Pacific Railroad at 328 miles (528 km), the 1,331 miles (2,142 km) Southern Pacific Railroad of Mexico, and a variety of 3 ft (914 mm) narrow gauge routes.