El Dorado is a city in and the county seat of Union County, Arkansas, USA. According to estimates, the 2012 census, the population of the city is 18,491, which represents a decline of 2.1 percent from the 2010 tabulation of 18,884.
El Dorado is headquarters of the Arkansas Oil and Gas Commission as well as Murphy Oil Corporation, Deltic Timber Corporation, and the Lion Oil Refinery. The city contains a community college, South Arkansas Community College ("SouthArk"), a multi-cultural arts center: South Arkansas Arts Center (SAAC), an award-winning renovated downtown, and numerous sporting, shopping, and dining opportunities. El Dorado is the population, cultural, and business center of the regional area. The city is best known as being the heart of the 1920s oil boom in southern Arkansas. Its nickname is "Arkansas’s Original Boomtown". El Dorado is located about from the state capital of Little Rock.