The maps in these pages are scans from the Oklahoma 2007 Centennial State Map produced by the Oklahoma Department of Transportation. A copyright notice does not appear on that map so my assumption is that they are freely distributable and copyable, which I've done here. These scans do not include the Legends, City Indices, or Mileage Table which are in the paper version but all other map elements are included.
Free copies of the paper version are available in the Visitors Area of the State Capitol among other places. The map also notes that,
Individual maps of Oklahoma counties and incorporated cities may be purchased from Oklahoma Department of Transportation, Printing Services, 200 N.E. 21st St., Oklahoma City, Oklahoma 73105, Telephone 405-521-2586.