Where was the first transcontinental railroad joined?

The first transcontinental railroad in the United States was joined at Promontory Summit, Utah, on May 10, 1869. The meeting point of the Central Pacific and Union Pacific railroads was marked by the ceremonial driving of the "Golden Spike," symbolizing the completion of the railroad that connected the eastern and western parts of the country. This monumental achievement significantly facilitated transportation and commerce across the nation.