K-126 begins at an intersection with US-400 and heads northward; south of this intersection, the roadway continues as Northwest 100th Street. The highway passes the small city of McCune on its eastern limit, then meanders slightly to the northwest before turning north again. It continues in this direction for about and then curves due east. Afterward, K-126 crosses Lightning Creek and continues east toward Pittsburg. Approximately east of Lightning Creek, the route intersects K-7, then crosses the BNSF Railway. K-126 continues east past the railway through flat, open plains. It then enters a lightly wooded area scattered with several small ponds and crosses Second Cow Creeken route to Pittsburg. Just inside the city limits of Pittsburg, K-126 crosses First Cow Creek. East of the creek is a four-lane highway that carries the US-69 and US-160 designations. K-126 intersects this road, then continues eastward into the city; the route is known as 4th Street inside the city limits. It serves a residential area in the western section of the city, then passes a library and enters the downtown section. Here, it meets U.S. Route 69 Business, then continues farther east. After leaving the downtown section of Pittsburg, K-126 passes over a railroad that serves both the South Kansas and Oklahoma Railroad and the Kansas City Southern Railway. The road runs south of a city park, then heads through another residential neighborhood. After passing Pittsburg High School, K-126 exits Pittsburg and crosses East Cow Creek. East of the city, K-126 travels through a hilly, lightly wooded area for about before it bends to the southeast and terminates at the Missouri state line. The road continues eastward into Missouri as Missouri Route 126 toward Golden City. K-126 is not included in the National Highway System. The NationalHighway System is a system of highways important to the nation's defense, economy, and mobility. K-126 does connect to the National Highway System at its junction with US-69 and US-160. 2017 Annual average daily traffic on K-126 ranged from 645 slightly south of McCune, 1110 slightly north of McCune, 1210 slightly west of the junction with K-7, 1210 near the Missouri border, 2900 slightly east of Pittsburg, 3320 slightly east of the junction with K-7, 5190 slightly west of the US-69/US-160 junction, 5280 slightly east of the US-69/US-160 junction, and 5360 slightly east of the US-69 Business junction.
History
In an October 11, 1940 resolution the section from Pittsburg east to the Missouri state line was designated as K-104. In a September 17, 1942 meeting it was approved to realign US-160 from south of McCune directly east to US-69 and then north through Pittsburg along US-69 and to extend K-104 west from Pittsburg along the old US-160. But then in a September 30, 1943 resolution that plan was cancelled due to restrictions imposed on the State Highway Commission caused by World War II. Also in that resolution US-160 was reinstated north through McCune then east to Pittsburg, K-103 was reinstated from MccCune east to K-7 then south along K-7 then east through Weir to US-69, K-104 was established from K-7 along the Cherokee-Crawford county line to US-69 and K-104 from US-69 in Pittsburg east to the Missouri line was designated as K-126. In a December 15, 1953 resolution K-126 was realigmed near the Missouri state line to eliminate two sharp curves. Then in 1958 US-160 was finally realigned east along K-103 from south of McCune to K-7 then continued east along K-104 to US-69 and at that time K-126 was extended along the old US-160 through McCune to end at the new US-160 south of McCune. In a December 1, 1994 resolution K-126's western terminus was co-designated as US-400 when US-400 was created. This overlap lasted roughly four years then in a December 3, 1998 resolution US-160 was realigned onto K-96 from Oswego eastward. Until 2003, K-57 originally overlapped US-69 through Pittsburg then in a May 14, 2003 resolution K-57 was truncated to US-169 in Colony and the overlap was eliminated.
