Sonny Richardson got a surprise last Thursday when the Mathews Post Office called and asked him to drop by.

When he walked into the building, said Richardson, post office employee Dawn Miller showed him a small envelope and asked him if it looked familiar. Richardson immediately recognized the handwriting. It was that of his mother, Betty Ann, who passed away in 2010.

The letter was postmarked Feb. 17, 1978, and the stamp had been canceled, but it had never reached its intended recipient—lifelong family friend Mary Bowman, who was then a student at St. Andrews College in Laurinburg, North Carolina. Long since married, she is now Mary Bowman Mapes of Atlanta, Georgia.

“It was a Christmas miracle,” said Richardson, a lifelong Mathews resident. He said the unexpected letter nearly brought him to tears. It was warm and chatty, written on a snowy day to bring Bowman up to date on the latest Richardson family news, from the arrival of a college yearbook to Sonny and his wife Connie...