El Dorado Lake is a reservoir on the Walnut River 0.5 miles (0.80 km) northeast of El Dorado in the Flint Hills region of Kansas. Built and managed by the U.S. Army Corps of Engineers, it is used for flood control, recreation, and water supply. El Dorado State Park is located on its shore.

K-177 is a 102.871-mile-long (165.555 km) south–north state highway in central Kansas. It runs from U.S. Route 54 (US-54) near El Dorado northward to US-24 in Manhattan, passing through the Flint Hills. It is part of the Flint Hills Scenic Byway and the Prairie Parkway.