High Quality Content by WIKIPEDIA articles! State Highway 6, abbreviated to SH-6 or OK-6, is a state highway in Oklahoma. It runs in a 116.4 mile (187.3 km) crescent through the southwestern part of the state, running from the Texas state line north of Quanah, Texas, to SH-152 in the unincorporated town of Sweetwater. There are no letter-suffixed spur highways branching from SH-6.