Eldorado, the county seat and largest city of Butler county, is beautifully situated on the Walnut river, a short distance northwest of the center of the county. The first known settler in the locality was William Hildebrand, who built a cabin there in the late '50s. His house became a rendezvous for men believed to be horse thieves, and in 1859 the place was raided by the settlers. Hildebrand was given a severe flogging and ordered to leave the neighborhood within 24 hours. He did not wait for a second notice.

Two houses were built where the city now stands in 1867, but the history of Eldorado begins with the year 1868. On March 23 of that year B. F. Gordy entered the land, and a little later sold Byron O. Carr, Samuel Langdon and Henry Martin each one-fifth of his claim, retaining two-fifths for himself. These four men formed a town company and the first lots were sold at $10 each. Several houses were erected before the close of the year. Elias Main established a sawmill on the Walnut river, and Henry Martin built the first frame house in the town. As soon as it was completed he put in a stock of goods—the first store in Eldorado. Town companies were common in those days, but Eldorado being situated at the crossing of the Fayetteville emigrant trail (sometimes called the California road), it soon outstripped its competitors. In 1869 Bronson & Sallee published the "Emigrant's Guide," calling attention to the advantages of Butler county, and to Eldorado in particular. 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 Sept. 12, 1871, Eldorado was incorporated as a city of the third class, J. C. Lambdin, who had been chairman of the board of trustees, acting as mayor until the election of Henry Falls. It was not many years before Eldorado became a city of the second class.

The Eldorado of the present day has 4 banks, an electric lighting plant, waterworks, a fire department, fine public school buildings, 2 daily and 3 weekly newpsapers, good hotels, well kept streets, a number of first class mercantile houses, a telephone exchange, some manufacturing interests, an international money order postoffice with four rural routes, telegraph and express service, a number of fine church edifices, and in 1910 reported a population of 3,129. The transportation and shipping facilities are excellent. A line of the Atchison, Topeka & Santa Fe system runs north and south through the city; a line of the Missouri Pacific runs east and west, and a branch of the same system runs from Eldorado to McPherson. With these lines radiating in five different directions, the city is in touch with markets and easily accessible.