Motorway 9 also known as the Outer Ring Road or Kanchanaphisek Road is a limited-access highway or motorway that links the outer fringes of Greater Bangkok.
The western route is a free section, which extends from RamaII Road (Route 35) at Bang Khun Thien through Bang Khae, Chim Phli, Bang Yai, Bang Bua Thong, Pathum Thani, Sam Khok and meets Phahon Yothin highway (Route 1) at Pratunam Phra-In interchange.