The Last Spike was driven at Promontory Summit, Utah, on May 10, 1869. This ceremony was termed the "wedding of the rails", and represented completion of the first transcontinental railroad in North America.

In 1851 the US Congress had ordered a survey to find the best route to build a transcontinental railroad. The selected route was through the middle of the country, near the 42nd parallel. President Lincoln signed the Pacific Railway Act July 1, 1862 to authorize construction. Rails and supplies for the western railway, the Central Pacific, had to be shipped around South America. The ties for the Union Pacific, which was building from the east side, had to be hauled over 1000 miles of rough terrain. Many Irish immigrants who had fled the potato famine in Ireland were employed by the Union Pacific, while Central Pacific had numerous Chinese workers.

At the Ceremony on May 10, 1869, special gold and silver spikes were placed in a laurelwood rail tie. As shown in the photo above, locomotives from each railroad were driven to the site for the ceremony. A collection of artifacts from the ceremony are now at Stanford University, donated by Leland Stanford, President of Central Pacific. Although the ceremony site is no longer part of the transcontinental railroad, it is recognized and protected as the Golden Spike National Historic Site.