At more than 1,000 square miles, Union County [†] is the state's largest geographically. Ninety percent of the county is forested. Forage and hay are raised for livestock, but no row crops are cultivated. Nearly one-quarter of the work force is employed in manufacturing, primarily in petrochemical, poultry processing, and wood products operations.
In November 1829, the territorial legislature formed Union County from parts of Hempstead and Clark counties. The next spring, the county court convened at the former colonial trading post of Ecore Fabre (now Camden in Ouachita County) on a bluff overlooking the Ouachita River. In 1837, county officers anticipated that a pending division of the county would slice away the Ecore Fabre region and approved the relocation of the county seat farther down the river to another port, Scarborough's Landing (later renamed Champagnolle). Over the following two decades, three counties and parts of six others were carved from the original Union County. Reflecting a changing economy, many residents in 1843 signed a petition requesting that the county seat be moved inland from the river floodplain and closer to major cotton farms. Three commissioners asked Matthew Rainey to surrender 160 acres he had preempted on a ridge that was the county's highest point, about twelve miles from the river. A surveyor platted the newly christened El Dorado, and officials approved $200 to build a courthouse on the town square.
† Encyclopedia of Arkansas, El Dorado (Union County), encyclopediaofarkansas.net, accessed November, 2021.