Oklahoma State Highway 4 Oklahoma State Highway 4 State Highway 4, abbreviated as SH-4 or OK-4, is a designation for two distinct highways maintained by the U.S. state of Oklahoma. One of them serves as an important route through the suburbs west of Oklahoma City, while the other connects US-259 to the Arkansas state line west of Cove, Arkansas. SH-4 has no lettered spur routes. The two SH-4s were never connected. The Central Oklahoma highway was established in 1941 and gradually extended to its present extent between then and 2003. The Eastern Oklahoma highway was originally numbered SH-21, and was renumbered to SH-4 in
Oklahoma State Highway 18 Oklahoma State Highway 18 State Highway 18, abbreviated as SH-18 or OK-18, is a highway maintained by the U.S. state of Oklahoma. It was once one of the longest state highways in the Oklahoma road system, but now has a total length of . State Highway 18 was commissioned in August 1924 and, at one time, traveled from Dickson, Oklahoma to Shidler, Oklahoma at the Kansas border. Much of SH-18 has been replaced by US-177. The current Highway 18 begins in Shawnee, Oklahoma at an interchange with US-177/270 and SH-3W. The highway is known as Harrison Street through Shawnee. After