Promontory is an area of high ground in Box Elder County, Utah, United States, 32Â mi (51Â km) west of Brigham City and 66Â mi (106Â km) northwest of Salt Lake City. Rising to an elevation of 4,902 feet (1,494Â m) above sea level, it lies to the north of the Promontory Mountains and the Great Salt Lake. It is notable as the location of Promontory Summit, where the first transcontinental railroad in the United States, from Sacramento to Omaha, was officially completed on May 10, 1869. The location is sometimes confused with Promontory Point, a location further south along the southern tip of the Promontory Mountains. Both locations are significant to the Overland Route: Promontory Summit was where the original, now abandoned, alignment crossed just north of the Promontory Mountains; while Promontory Point is where the modern alignment, called the Lucin Cutoff, crosses the southern tip of the Promontory Mountains.
By the summer of 1868, the Central Pacific (CP) had completed the first rail route through the Sierra Nevada mountains, and was now moving down towards the Interior Plains and the Union Pacific (UP) line. More than 4,000 workers, of whom two thirds were Chinese, had laid more than 100Â mi (160Â km) of track at altitudes above 7,000Â ft (2,100Â m). In May 1869, the railheads of the Union Pacific and the Central Pacific railroads finally met at Promontory Summit, Utah Territory. A specially-chosen Chinese and Irish crew had taken only 12 hours to lay the final 10Â mi (16Â km) of track in time for the ceremony.