Union County, Arkansas: History
Union County was formed on November 2, 1829, from portions of Clark and Hempstead counties. Areas along the waterways were originally developed for cotton plantations in the antebellum years, and planters depended on large groups of enslaved African-American workers to generate their profits.
On January 10, 1921, Dr. Samuel T. Busey hit oil with a well about a mile south of El Dorado, leading to an oil boom that attracted thousands of workers and speculators. His first well produced for fewer than two months, but by 1923, "El Dorado boasted fifty-nine oil contracting companies, thirteen oil distributors and refiners, and twenty-two oil production companies. The city was flooded with so many people that no bed space was available for them, leading to whole neighborhoods of tents and hastily constructed shacks to be erected throughout the city. The city's population reached a high of nearly 30,000 in 1925 during the boom before dropping to 16,241 by 1930 and rising to 25,000 by 1960." Oil production fell markedly in the early 1930s, in part due to companies' financial difficulties during the Great Depression. It recovered later in the decade.
During World War II, chemical plants were established in the county, but their production declined after the war. Exploitation of Arkansas forests led to growth in the timber industry in the county. Oil, chemical and timber industries are still important to the economy, although in lesser proportion.