As reported by the Smithsonian National Postal Museum:
This saddlebag was used by a rural letter carrier at the turn of the last century in Virginia. While the outside of the saddlebag is innocuous enough, flipping open the mailbags on each side reveal a disturbing reality. One of the bags is marked by hand, “White,” the other “Colored.”
The saddlebag was used by a rural carrier operating out of the Palmyra post office in Fluvanna County, Virginia, most probably by Frank W. Shepherd (1868-1931)... Shepherd and Howard began working their routes on October 22, 1896 at an annual salary of $200 each. Each man’s route covered about 15 miles, with a total of 350 patrons on both routes.
Shepherd worked as a rural carrier on the route until his retirement in 1921. According to the “Annual Report of the Postmaster General,” the Palmyra rural routes were difficult to traverse. “The roads are scarce and bad. In covering their routes the carriers have to take their horses through fields and over farms.” Then, as now, rural carriers were responsible for supplying their own transportation and equipment. Shepherd either already owned this saddlebag or purchased it for carrying mail on his route. Why Shepherd segregated the mailbags is unknown. He may have done it because of personal prejudices, or by the demands of white patrons who did not want their mail to be “mixed” with letters addressed to their African American neighbors.