El Dorado is a Spanish term meaning "the golden." The naming of El Dorado, Kansas (pronounced "el doe-RAY-doe") is far removed from the mythical land of gold. Merely a coincidence, El Dorado received its name long before the historic discovery of "black gold" in 1915.
El Dorado's original town site was located one and one half mile south of the present day community. In June 1857 a group of residents from Lawrence, Kansas traveled to Butler County to settle the unpopulated territory. The travelers made their way to the Walnut River where two pioneer trails crossed—the California Trail and the Osage Trail.
During the journey Captain J. Cracklin, a member of the colony, exclaimed "El Dorado" at the beautiful appearance of the country. When the town site was selected a vote was taken and the name El Dorado was approved. For the next twelve years El Dorado remained the farthest western outpost in Kansas.
During those twelve years Kansas became the 34th state, the Civil War began in 1861 and settlement of the area came to a halt. After the end of the Civil War, in 1868 B.F. Gordy platted the present day town site. In 1870 there was an influx of settlers and the town was enlarged by several additions. On March 4, 1870, the first number of the Walnut Valley Times was issued, a flour mill was established and the town began to assume an appearance of permanency. The growth continued and on September 12, 1871, El Dorado was incorporated as a city of the third class. Early residents of El Dorado survived a tornado, won the battle for the county seat in the early 1870s and endured the 1874 grasshopper invasion.
Although now known for its early twentieth-century role in the state's oil and gas industry, El Dorado's nineteenth century economy was tied closely to its role as a railroad and trade center for the region's thriving farming and ranching industries. In 1877, the Atchison, Topeka and Santa Fe Railroad completed the line from Florence to El Dorado. In 1883, the St. Louis, Fort Scott and Wichita Railroad completed a line between El Dorado and Wichita. By 1913, El Dorado had rail lines radiating in five different directions.
The protein rich grasses of the Flint Hills made El Dorado and surrounding communities a prime location for the cattle industry. Ample farmland and a drought resistant crop called Kafir corn (related to milo and sorghum) created an agricultural boom in the late 1800s and early 1900s.
El Dorado's next boom began when the Stapleton #1, the discovery well of the historic El Dorado Oil Field, struck black gold in 1915. Small boom towns popped up overnight and El Dorado's population soared. The El Dorado Oil Field remains one of the world's oldest continually producing oil fields.