The First Transcontinental Railroad (known originally as the “Pacific Railroad” and later as the “Overland Route”) was a 1,907-mile (3,069 km) contiguous railroad line constructed in the United States between 1863 and 1869 west of the Mississippi and Missouri Rivers to connect the Pacific coast at San Francisco Bay with the existing eastern U.S. rail network at Council Bluffs, Iowa. The rail line was built by three private companies largely financed by government bonds and huge land grants: the original Western Pacific Railroad Company between Oakland and Sacramento, California (132 mi or 212 km), the Central Pacific Railroad Company of California eastward from Sacramento to Promontory Summit, Utah Territory (U.T.) (690 mi or 1,110 km), and the Union Pacific westward to Promontory Summit from the road’s statutory Eastern terminus at Council Bluffs on the eastern shore of the Missouri River opposite Omaha, Nebraska (1,085 mi or 1,746 km).
Opened for through traffic on May 10, 1869, with the ceremonial driving of the “Last Spike” (later often called the “Golden Spike”) with a silver hammer at Promontory Summit, the road established a mechanized transcontinental transportation network that revolutionized the settlement and economy of the American West by bringing these western states and territories firmly and profitably into the “Union” and making goods and transportation much quicker, cheaper, and more flexible from coast to coast.
Paddle steamers linked Sacramento to the cities and their harbor facilities in the San Francisco Bay until 1869, when the CPRR completed and opened the WP grade (which the CPRR had acquired in 1867–68 [N 1]) to Alameda and Oakland (MP 6).
The first transcontinental passengers arrived at Alameda Wharf on September 6, 1869, where they transferred to the steamer Alameda which carried them across the Bay to San Francisco. On November 8 of the same year, the western terminus of the railroad was changed to Oakland Wharf. Service between San Francisco [MP 0] and Oakland Pier [MP 6] would continue to be provided by ferry.
The CPRR eventually purchased 53 miles of UPRR-built grade from Promontory Summit (MP 828) to Ogden, U.T. (MP 881), which became the interchange point between trains of the two roads. The transcontinental line was popularly known as the Overland Route after the principal passenger rail service that operated over the length of the line until 1962.