The legendary Pony Express only operated for eighteen months

Relays of horseback riders carried mail 1,900 miles between Missouri and California in about 10 days, a stunning improvement on existing routes. It launched in April 1860 to huge fanfare — and folded eighteen months later, in October 1861, the same week the transcontinental telegraph was completed. The instant wires could carry a message coast to coast, galloping horses simply couldn't compete.

— Standard historical accounts, Pony Express — April 1860 – October 1861