El Dorado
- County:
- Butler County
- County Seat:
- Yes
- Area (mi²):
- 9.952
- State:
- Kansas
El Dorado is a city located in Butler County, Kansas. El Dorado has a 2026 population of 12,694. It is also the county seat of Butler County. El Dorado is currently declining at a rate of -1.14% annually and its population has decreased by -0.6% since the most recent census, which recorded a population of 12,771 in 2020.