The highway begins in front of THSR Chiayi Station in Taibao City as HSR Avenue, which connects the station with downtown Chiayi City. The highway continues eastbound as it leaves Chiayi City for Alishan. In Zhongpu the highway has a junction with Freeway 3. The road then passes through Fanlu and Zhuqi before reaching Alishan Township, home to the popular tourist destination of Alishan National Scenic Area and Alishan Forest Railway. The highway then continues eastbound through the Alishan mountains and enters Yushan National Park, before ending at the junction of PH 21 in Tatajia, located near the foot of Yushan, the highest mountain in Taiwan.