As more people rushed their way westward in mid-1800s, communication between nation's two coasts became paramount for the Union. Messages needing to reach their destination faster found horseback riders to be an effective medium, forming the famed Pony Express.

Connecting Missouri to California, the Pony Express crossed eight states. However, it actually bypassed Arizona. Nonetheless, the tradition has lived on in Arizona where riders still deliver mail. The service is the only U.S. Postal Service-sanctioned Pony Express in the country.

In this episode of Valley 101, a podcast by The Arizona Republic and azcentral.com, we learn about a special horse-riding unit in northern Arizona that brings down mail to the Valley each year.

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