Postal service was established in the Decatur County town of Weldon on February 14, 1881, when an office was established in a room adjacent to the L.G. Jamison general store. In the 1920s, the post office moved to the east side of the square before moving to an old bank building, wich it occupied for over 50 years. The Weldon Post Office experienced a robbery in the spring of 1935:

Postmaster Ora Garton and her husband discovered the theft when they entered the post office on the morning of Saturday, March 1, 1935. The safe was blasted open, the combination was blown across the room, drawers had been rifled and papers were scattered about the floor. $800 in money and stamps were taken as well as other valuables. Entrance to the building was made by prying open a rear window. No fingerprints were available, and there is no record that this robbery was ever solved.

The post office occupied the former bank building until November 1, 1999, when services were moved to a new modular building along Decatur County Road J12.