El Dorado State Park is a state park in Butler County, Kansas, United States, located just north of El Dorado. The largest of Kansas' state parks, El Dorado is nestled in the scenic Flint Hills and sprawls across 4,000 acres (16 km²) along the eastern and western shores of El Dorado Reservoir. Crappie and largemouth bass fishing are good in standing timber and around fish attractors. Walleye fishing is good along the face of the dam and on the old railroad bed.