Founded July 1, 1862, when President Lincoln signed the Pacific Railway Act, Union Pacific has been building America for more than 150 years.Starting with the construction of the first transcontinental railroad, surviving the country's multiple economic crises, supporting America's military men and women through conflicts and forging forward to overcome hurricanes, floods and droughts, Union Pacific remains a trusted mainstay on America's landscape.

The Union Pacific was largely financed by federal loans and land grants, but it overextended itself through its involvement in the Crédit Mobilier scandal, in which a few manipulators reaped enormous profits. After exposure of the scheme, which left the railroad badly in debt, the company went into receivership in 1893. It was reorganized in 1897 under the leadership of Edward H. Harriman, who was responsible for major improvements and standardization and who led the railroad to participate in the economic development of the West. Harriman used the railroad as a holding company for the securities of other transportation companies in his empire. His son, W. Averell Harriman, was chairman of the board of Union Pacific from 1932 to 1946.

The Union Pacific grew to operate in 13 western states, extending from Council Bluffs, Iowa, and Kansas City, Missouri, to Portland, Oregon, and Los Angeles. Since 1969 it has been owned by the Union Pacific Corporation, a holding company.

In 1982 the Union Pacific merged with two other railroads, the Missouri Pacific Railroad Company (headquartered in St. Louis, Missouri) and the Western Pacific Railroad Company (headquartered in San Francisco), to form what came to be called the Union Pacific System. Western Pacific became a subsidiary of Union Pacific at this time, while Union Pacific and Missouri Pacific retained their separate corporate identities until the merger was completed in 1997. At that time, traffic control and marketing for all three railroads were fully unified, and all lines operated under the Union Pacific name. With its acquisition of the Southern Pacific Rail Corporation in 1996, Union Pacific became the largest domestic railroad in the United States, controlling almost all of the rail-based shipping in the western two-thirds of the country. It carries products and commodities such as coal, automobiles, foods, forest and agricultural products, and chemicals and is one of the largest intermodal shippers (including truck trailers and containers) in the country. Corporate headquarters are in Omaha, where Union Pacific laid its first rails in 1865.

This is the story of the first transcontinental railroad; the greatest, most daring engineering effort the country had yet seen. The time was the 1860s. Imagine the task. The idea was to span the West with iron rails from Omaha to Sacramento, to build a railroad across two-thirds of the continent and some of the most difficult terrain on earth. 'Ruinous space,' a Boston paper called it. Not in all that distance, not in 1,700 miles, was there a single settlement of any appreciable size except at Salt Lake. The railroad would join what essentially were two different countries: California and back East. Construction crews would cross hundreds of miles of desert – push into the mountains at elevations as high as 8,000 feet. It's hard to believe that one river alone, the Weber, would have to be crossed 31 times. And all this without benefit of bulldozers or rock drills, modern explosives or modern medical facilities. They called it a work of giants. But like all great stories, it's about people: construction bosses, politicians, thousands of workers and the people who got the whole thing started in the first place."