Counties Passed through: Coffey, Osage, Franklin, Douglas, Johnson
Origionally, K-33 met US 50 at Edgerton, came through Ottawa and journeyed southwest through Homewood, Ransomville, Williamsburg, and Silkville before ending at US 75 west of Waverly. The entire route was gravel, except that the route was being hard-surfaced west out of Ottawa, reaching Williamsburg by 1933.
By 1936, K-33 was realgned to meet US 50 in Douglas County north of Wellsville and the segment west of the junction with K-68 into Ottawa was re-designated as an extension of K-68, with the rest of the route (which had been hard-surfaced all the way to Waverl7) re-designated as US 50S.
K-33 was hard-surfaced north of Wellsville by 1940, and hard-surface in its entirty by 1950.