The Pony Express was a heroic undertaking, but the coming of the telegraph secured its fate. The young riders were fast, but electricity was instantaneous, and the express mail service closed two days after the transcontinental telegraph line began operations in October 1861. The following -advertisement appeared in the 26 March 1860 issue of the St. Louis Republic:

To San Francisco in 8 days by the Central Overland California and Pike's Peak Express Company. The first courier of the Pony Express will leave the Missouri River on Tuesday April 3rd at 5 o'clock P.M. and will run regularly, weekly thereafter, carrying a letter mail only. The - point of departure . . . will be in telegraphic connection with the East and will be announced in due time.