The most unusual delivery method used by USPS is a mule train in Arizona. The mules carry mail, food and supplies down an 8-mile trail to the Havasupai Indians at the bottom of the Grand Canyon.
Elf / Wikipedia, Tiny Fox Lab

The most unusual delivery method used by USPS is a mule train in Arizona. The mules carry mail, food and supplies down an 8-mile trail to the Havasupai Indians at the bottom of the Grand Canyon. – Tiny Fox Lab Facts

Preview photo credit: Elf / Wikipedia
Source: usps.com/8-mile-mule-train…