Arkadelphia is a city located in Clark County, Arkansas. According to 2006 Census Bureau estimates, the population of the city is 10,548. The city is the county seat of Clark County.
The site was settled in about 1811 by John Hemphill, operator of a nearby salt works. It was known as Blakelytown until 1838, when the settlement adopted its present name of Arkadelphia.
The city's name Arkadelphia was formed by combining Ark- from the state's name Arkansas and adelphia as in Philadelphia. Several towns in the area took similar names (e.g., Dalark, named for its location in Dallas County, Arkansas).