K-16 is a 114.460-mile-long (184.206 km) state highway in the U.S. State of Kansas. K-16's western terminus is at a junction with U.S. Route 77 (US-77) just north of Randolph and the eastern terminus is at US-24 and US-40 in Tonganoxie. Along the way K-4 intersects many major thoroughfares including US-75 in Holton, K-4 near Valley Falls and US-59 from west of Winchester to south of Oskaloosa.

U.S. Route 40 (US-40) is a part of the U.S. Highway System that runs from Interstate 80 (I-80) and US-189 in Silver Summit, Utah east to US-322 and Ocean Drive in Atlantic City, New Jersey. In the U.S. state of Kansas, US-40 is a main east–west highway that runs from the Colorado border east to the Missouri border. The highway is concurrent with Interstate 70 (I-70) from Oakley to Topeka, and again through Kansas City.