Promotory Summit achieved note as the location where the United States' first transcontinental railroad was completed on May 10, 1869, with the driving of the Golden Spike, joining the Union Pacific and Central Pacific railroads.
Promontory was the site of a temporary city during and shortly after the construction of the railroad, but this was then dismantled, and since then Promontory has had no permanent population.
Since 1957 it has been preserved as part of the Golden Spike National Historic Site.
Important note: This place is often called Promontory Point, however that is a separate location at the southern tip of a peninsula (promontory) in the Great Salt Lake, which is not where the railroads met.