The Pony Express was a way people sent messages across the United States in the 1800s. There were a series of relay stations set up between the East and West Coasts that kept the mail moving quickly. People called them "pony stations" because there was a line of horses between the stations that would quickly bring mail from one to the other. Every station was about 10 miles apart and the mail traveled almost 2,000 miles in just 10 to 12 days! When a rider reached the next station, a fresh horse waited for them so they could continue the journey. The Pony Express only lasted 18 months, but it showed how horses could help with long-distance communication at a time when there were no telephones or email.