The Federal Route 1 is the main trunk road at the interior part of Peninsular Malaysia but passes the western states. From Tampin to Sungai Siput, the FT1 highway runs along the western foothills of the Titiwangsa Range. The FT1 highway intersects with the Federal Route 2 at Kuala Lumpur before intersecting with another end of the Federal Route 5 at Ipoh. At Sungai Siput, Perak, the route changes its direction westbound and later become the main west coastal route, starting from Changkat Jering, Perak to Alor Setar, Kedah. The route meets with the North–South Expressway Northern Route E1 at Jitra, Kedah and the section of the North–South Expressway from Jitra to Bukit Kayu Hitam is a part of the Federal Route 1.