K-18 begins near the town of Bogue in
Graham County as it branches off to the south from US-24. The highway then stairsteps to the southeast through the towns of Damar, Palco, Plainville, and Codell in Rooks County; Natoma in Osborne County; Paradise, Waldo, Luray, and Lucas in Russell County (K-18 is duplexed with US-281 for west of Luray); and Sylvan Grove, Lincoln, and Beverly in Lincoln County. As K-18 enters
Ottawa County, it takes a due east bearing, traveling through Tescott and meeting US-81 north of Salina. The road briefly jogs to the north for around before turning east again to travel through Bennington and Talmage in Dickinson County and into Junction City in Geary County. In Junction City, K-18 meets US-77 and travels south along US-77 through the city until it hits I-70. K-18 then travels to the northeast along I-70 for before exiting and continuing to the northeast toward
Manhattan as a freeway. K-18 crosses the Kansas River at the Riley County line and travels through Ogden into Manhattan. Once traveling through Manhattan, K-18 again crosses the Kansas River and parallels the river to the south into Wabaunsee County before ending at K-99 south of Wamego. The section of K-18 from just east of the interchange with K-113 to K-177 within Manhattan is maintained by the city. ==History==