K-161 is a 17-mile-long Kansas state highway linking US 36 in northern Kansas to the Nebraska border. At the Nebraska border, Nebraska Highway 61 takes the road north into Nebraska.

K-161 begins at US 36 in the northwest part of Bird City. The first nine miles (14 km) of the highway follows a due north course. After that, the highway curves slightly to the west through a series of hills. After clearing the hills, the highway resumes a due north course for a further 7.2 miles (11.6 km) to the Nebraska state line. North of the line, the road becomes N-61.