The entire highway is known as The Northern Coastal Highway or simply Coastal Highway to the locals, although various names are given for specific stretches of the road. The stretch from Tamsui to Jinshan is also known as Tamsui-Jinshan highway, while the stretch from Jinshan to Keelung City is known as Keelung-Jinshan highway.
The highway begins at Guandu Bridge, which is also the terminus of PH 2b and PH 15. It bypasses through downtown Tamsui and continues along the northern coasts of Taiwan, passing through Sanzhi, Jinshan, and Wanli. The road goes to the tourist destination of Baisha Bay, Yehliu, and Yehliu Promontory before entering Keelung City. In Keelung, the road goes through the downtown area as well as Port of Keelung before leaving for the northeastern New Taipei City. The highway continues along the coast, passing through Ruifang and Gongliao in New Taipei City. This stretch of the highway provides one of the most scenic views along the road. The scenic spots along the road include Cape Fugui, Cape Bitou, Cape San Diego Lighthouse, Fulong Beach, Dragon Cave, among others. The road continues on to Yilan County.
Yilan County
The road mostly follows a north-south direction along the coast in the county. It passes through rural and suburban townships of Toucheng, Zhuangwei, Wujie before ending at PH 9 in Su'ao. The road is one of the main highways connecting Keelung and Taipei with Yilan.
The highway has 7 spur routes. Each route use the same number, followed by a heavenly stem character. In English, these characters are replaced by letters in alphabetical order.
: This route is the old Highway 2 segment that continues on to Taipei. The route starts from downtown Taipei and ends in Tamsui. Within Taipei the road follows Chongqing North Road, Chengde Road and Dadu Road before entering Tamsui. The road goes into downtown Tamsui before ending at the junction of Highway 2. The total length is 21.660 km.
: This route is a mountain bypass of the parent route for the stretch between Keelung and Gongliao. The road starts at the junction of PH 2D in southern Keelung and ends at Highway 2 in Gongliao. It connects the mountain towns in northeast New Taipei, including Pingxi, Shuangxi and Gongliao. The total length is 29.957 km.
: This route connects National Highway No. 1 and Highway 2, bypassing downtown Keelung. The road runs parallel with PH 62, a limited-access expressway that was built to alleviate the traffic on PH 2D. The total length is 13.390 km.
: This route is the old Highway 2 segment in Yilan County, and goes from Wujie to Su'ao. The route runs parallel with its parent highway. The total length is 12.077 km.
: This route connects Port of Keelung and National Highway No. 3 and is used as an alternate route for trucks. This is the only provincial highway that is entirely a limited-access road. The road is entirely within Keelung City. The total length is 4.219 km.
: This route connects National Highway No.5, Highway 9 and Highway 2 in Yilan County. The road is entirely within Toucheng. The total length is 3.741 km.
