The Southern Pacific Transportation Company (reporting mark SP), earlier Southern Pacific Railroad (1865-1885) and Southern Pacific Company (1885-1969), and usually simply called the Southern Pacific Railroad, was an American railroad. The railroad was founded as a land holding company in 1865, forming part of the Central Pacific Railroad empire. By 1900, the Southern Pacific Company had grown into a major railroad system which incorporated many smaller companies, such as the Texas and New Orleans Railroad and Morgan's Louisiana and Texas Railroad, and which extended from New Orleans through Texas to El Paso, across New Mexico and through Tucson, to Los Angeles, throughout most of California including San Francisco and Sacramento; it absorbed the Central Pacific Railroad extending eastward across Nevada to Ogden, Utah and had lines reaching north throughout and across Oregon to Portland. The Southern Pacific had noticeable social impact along its route: some towns prospered because of it and it founded a number of important hospitals in, among other places, San Francisco and Tucson. Southern Pacific's total route mileage has varied significantly over the years. In 1929, the system showed 13,848 miles (22,286 km) (on its own) of track. Before the D&RGW merger Southern Pacific's mileage remained relatively unchanged at 12,912 miles (20,780 km). This reduction in mileage was mainly due to the pruning of branches. But by combining the mileage of subsidiary, Cotton Belt, this left the SP system with around 15,092 miles (24,288 km). This was due to the fact that the Cotton Belt had almost doubled in size to 2,180 miles (3,510 km) with the purchase of the Golden State Route. The takeover of Southern Pacific by Rio Grande Industries, along with the addition of the SPCSL route from Chicago to St. Louis, swelled the combined D&RGW/SP/SSW system to 17,340 miles (27,910 km). While the Cotton Belt is the most famous of Southern Pacific's subsidiaries, SP owned many others like the Northwestern Pacific at 328 miles (528 km), the 1,331 miles (2,142 km) Southern Pacific Railroad Company of Mexico, and a variety of narrow gauge routes.