Sunny Bryant is seen delivering a postcard to Charleen Brown in this undated photo. Courtesy of Charleen Brown

A postcard mailed in 1940 and delivered this week gives new meaning to the phrase "snail mail," but also to the Post Office vow that the mail must go through - eventually.

The card, addressed to Florence Marion, was finally delivered to her great-grandson Alan Marion 74 years late.

Records show the postcard was mailed on Feb. 20, 1940 - with a once cent stamp - from Portland, Ore. The card arrived at the Butte Falls, Ore., post office July 2013 and was uncovered by Sunny Bryant, a new USPS employee.

"I was overwhelmed with the job at that point, so to come across the postcard was just a shock," said Bryant. "My first response was what am I supposed to do with this?"

Bryant held on to the letter until later that summer when she overheard a member of the Rogue Valley Genealogical Society, Charleen Brown, discussing her work at the post office. Sunny Bryant decided to approach Brown and showed her the relic.

"It was such an exciting coincidence," said Brown. "After she showed me the postcard, I did some research, looking at the 1940 census. It then dawned on me that one of our newest members of the RVGS has the last name 'Marion.'"

Brown then contacted Alan Marion, a resident of Phoenix, Ore., who confirmed that he had a great grandmother by the name of Florence.

"I was very elated, very pleased to see the letter," Marion told ABC News. "I have very little in the way of mementos from my father's side of the family. I felt like my great-grandmother was looking over my shoulder and had something to do with it."

Courtesy of Alan Marion

Why the postcard took so long to reach its destination remains unclear. USPS official Bryant postulated that the postcard ended up unnoticed somehow before being put back into the mail.

"The letter was in fairly decent shape. It looked like it has been in kept inside, untainted by rain and other weather elements," said Bryant.

The front of the postcard is a picture of a boat with the words "Leaving Manilla Bay. Feb. 1906. Flying Homeward Pennant."

The back of the card has in pencil, "Arrived in Portland at 8 o'clock. Having a fine time. Be home sometime Sat. -Blanche."

Based on the tone of the letter, Marion guessed that Blanche was a member of his family. With the help of the Genealogical Society, Marion learned that Blanche was his likely great-grandmother's neighbor.

"I'm probably the oldest living family member on my father's side," said Marion. "I've been doing research, trying to learn more about my family for the last five years. I am so pleased to have this postcard connecting me to them."

Butte Falls is a community with only 350 residents, which made it much simpler to trace the postcard's origins.

"If this was found somewhere like Los Angeles, I don't think we would have been able to pin down where it came from as easily," Brown chuckled.