Arkadelphia was settled in the 19th century, with a post office opening in 1854. It was initially located with Blount County. The town's etymology is disputed. Some believe Arkadelphia was the name of the wife of the first postmaster John A. Donaldson. Some believe it is a combination of "Ark-", the name of an early settlement in nearby Winston County, and "-adelphia", a pseudo-Greek combination meaning "brother-place," likely taken from Philadelphia.[2] There is no known connection to Arkadelphia, Arkansas, an incorporated city founded in 1809 and renamed Arkadelphia in 1839. After redrawing the county lines around 1900, it was shifted into Cullman County.
Railroad engineer J.E. Willoughby was born in Arkadelphia in 1871.
Arkadelphia first appeared on the 1880 U.S. Census as an unincorporated village within Blount County.[4] The population of the village made it the second largest community in the county behind the then-county seat of Blountsville. The village did not report again on the census, although the precinct bearing its name appeared in 1890 and continued to report until 1950. See precinct below.
The Arkadelphia Precinct (Blount County 24th Precinct) first appeared on the 1890 U.S. Census.[6] With the redrawing of the county lines after 1900, and Arkadelphia's shift into Cullman County, the new 7th precinct of Cullman County bore the name of Arkadelphia and continued to report on the census from 1910 to 1950. In 1960,[7] the precinct was merged as part of a larger reorganization of counties into the census division of Bremen.