The simple message was dispatched at 12:47 P.M.: "Done." That unusually brief telegraphic notice on May 10, 1869, set off what may have been the most widespread celebration the United States had witnessed to that time. Fifty tugboats whistled salutes as they paraded along the lakefront in Chicago; New Yorkers shouted with glee at the conclusion of a 100-gun salute; the national capital staged banquets, parades, and a spectacular fireworks display; and prayers and toasts were intermingled throughout the thirty-seven states and territories. . . (T)he event. . . was the completion of the country's first transcontinental railroad. The rails joined at Promontory, a desolate, windswept, and heretofore unremarked spot in what became the state of Utah. . . (Hofsommer, Don L. The Southern Pacific, 1901-1985. Texas A&M University Press. 1986.)
The golden spike would not have been driven at Promontory had the Union Pacific not encountered an obstacle as it worked its way to a junction with the Central Pacific. That obstacle was the Great Salt Lake. Union Pacific toyed with the possibility of crossing the lake, but ultimately chose a less challenging alternative:
(T)hey [Union Pacific engineers] discussed a little, though perhaps more jocularly than seriously, the feasibility of driving straight across the lake, or at least across its eastern arm. Of course they gave it up. The idea then was almost chimerical. There was neither the genius in finance bold enough to undertake such a stupendous work, nor the traffic to warrant such an expenditure. It may be doubted, too, if there was engineering faith equal to the task. So the line was built up through the hills around the north end of the lake. (Davis, Oscar King. "The Lucin Cut-Off". The Century Magazine. Jan, 1906, p. 459)
One might say that Promontory owed its moment of glory on the nation's stage to the Great Salt Lake. Promontory's place in the limelight came to an end when Southern Pacific successfully crossed the Great Salt Lake via the Lucin Cutoff.