K-18 is a 206-mile (332 km), west–east state highway in the U.S. State of Kansas. K-18's western terminus is at U.S. Route 24 (US-24) near Bogue and the eastern terminus is at K-99 south of Wamego. Portions of the highway have been upgraded to a freeway beginning in 2012.

K-99 is a state highway in the U.S. state of Kansas. The highway runs 234.473 miles (377.348 km) from Oklahoma State Highway 99 (SH-99) at the Oklahoma state line near Chautauqua north to Nebraska Highway 99 (N-99) at the Nebraska state line in Summerfield. K-99 connects Emporia with several smaller county seats to the south and north, including Sedan, Howard, Eureka, Alma, and Westmoreland while passing through the Flint Hills of eastern Kansas.