Oklahoma State Route 9 runs east-west through Northern Mc Clain County. This highway enters the county from Cleveland County on Interstate 35 at the Canadian River Bridge and runs west to the H.E. Bailey Turnpike Spur. OK St Rt 9 passes through the following town in Mc Clain County. Newcastle OK St Rt 9 is multi-plexed in Mc Clain County. Interstate 35, at the Cleveland/Mc Clain County Line. U.S. Rt. 62, from near Newcastle to the Mc Clain/Grady County Line. U.S. Rt. 277, from near Newcastle to the Mc Clain/Grady County Line. OK St Rt 9 intersects the following highwyas in Mc Clain County. H. E. Baily Turnpike Spur, near Newcastle. U.S. Rt. 62, near Newcastle. U.S. Rt. 277, near Newcastle. Interstate 35, at Newcastle.