Expressway No.15
Seohaean Expressway 서해안고속도로
Route information
Length	346.1 km (215.1 mi)
Existed	1994–present
Major junctions
South end	Mokpo, Jeonnam Province (Mokpo IC) National Route 1
Major intersections	Namhae Expressway Muan-Gwangju Expressway Gochang-Damyang Expressway Seocheon-Gongju Expressway Dangjin-Yeongdeok Expressway Pyeongtaek-Siheung Expressway Pyeongtaek-Jecheon Expressway Yeongdong Expressway Seoul Ring Expressway Second Gyeongin Expressway
North end	Geumcheon, Seoul (Geumcheon IC) Seobu Urban Expressway
Location
Country	South Korea
Major cities	Gimje, Gunsan, Boryeong, Seosan, Dangjin, Pyeongtaek, Hwaseong, Ansan, Anyang
Highway system
Highway systems of South Korea Expressways National Local

The Seohaean Expressway (Korean: 서해안 고속도로; Seohaean Gosok Doro), meaning "West Coast Expressway", is a freeway in South Korea, connecting Mokpo to Gunsan, Dangjin, and Seoul.

It is numbered 15. The entire length from Seoul to Mokpo is 345 km and the posted speed limit is 110 km/h, enforced primarily by speed cameras. It is connected of Seohae Grand Bridge in Pyeongtaek to Dangjin.

The branch expressways of the Seohaean Expressway are Seocheon–Gongju Expressway and Pyeongtaek–Siheung Expressway.

Typical facilities of this expressway is Seohae Bridge(Korean: 서해대교; Seohae Daegyo) which the total length of 7.3 km linking the Pyeongtaek(Gyeonggi Province) and Dangjin(Chungnam Province). The bridge is the third long bridge in the Republic of Korea.

The highway is a major highway linking the Seohaean Region(서해안권) for the first north–south axis (남북 제1축), the road through the South Jeolla Province, North Jeolla Province, South Chungcheong Province, Gyeonggi Province.

History

• December 1991 – Construction begin
• May 1993 – Construction begin of Seohae Grand Bridge
• 6 July 1994 – Seoul–Ansan segment opened to traffic.
• 17 December 1996 – Ansan–Pyeongtaek segment opened to traffic.
• 25 August 1998 – Mokpo–Muan segment opened to traffic.
• 30 October 1998 – Gunsan–Seocheon segment opened to traffic.
• 10 November 2000 – Seohae Grand Bridge segment opened to traffic. and Pyeongtaek–Dangjin segment opened to traffic.
• 27 September 2001 – Dangjin–Seocheon segment opened to traffic.
• 21 December 2001 – The last segment, Gunsan–Muan segment opened to traffic.
• 30 July 2010 – Work begins to widen to 8 lanes in Ansan–Iljik Junction.
• 23 November 2011 – Jungnim Junction opened to traffic.
• October 2014 – Seohae Bridge – W. Pyeongtaek Junction Section (10.3 km) road expansion started construction.
• November 2014 – The 10-lane expansion of the Ansan JCT – Jonam JCT (2.9 km) section was completed.
• June 2015 – The 10-lane expansion of the Jonam JCT – Mokgam IC (3.2 km) section was completed.
• 23 December 2015 – The 10-lane expansion of the Mokgam IC – Iljik JCT (3.8 km) section was completed.
• 3 July 2016 – Soha Junction opened to traffic.

Compositions

Lanes

• Mokpo IC – Dangjin JC, Iljik JC-West Seoul End: 4
• Dangjin JC – Bibong IC, Maesong IC-Ansan JC, Jonam JC–Mokgam IC: 6
• Mokgam IC – Iljik JC, Bibong IC – Maesong IC, West Seoul TG-Jonam JC: 8
• Ansan-Iljik, Yangjae-Giheung, unjung Bridge and Seoul Ring Road (Rigid Pavement) 130 km JC –  : 10

Length

346.1 km (215.1 mi)

Speed limits

• Jungnim JC – Maesong IC : 110 km/h
• Maesong IC – Seoul(Geumcheon) : 100 km/h
• Mokpo – Jungnim JC : 90 km/h

List of facilities

• IC: Interchange, JC: Junction, SA: Service area, TG:Tollgate

No.	Name	Korean name	Hanja name	Connections	Distance		Notes	Location
Connected directly with National Route 1, National Route 2(Goha-daero)(고하대로)
	Mokpo	목포 시점	木浦 始點	National Route 1 National Route 2 Mokpo Bridge Aphae Bridge	–	0.0		Mokpo	Jeonnam
1	Mokpo IC	목포나들목	木浦나들목	National Route 1 (Yeongsan-ro)	0.26	0.26
	Jungnim JC	죽림분기점	竹林分岐點	Namhae Expressway (Mokpo–Gwangyang) National Route 2 Jeonnam Provincial Office Mokpo Airport	3.90	4.16		Muan
2	Illo IC	일로나들목	一老나들목	Local Route 815	2.10	6.26
TG	Mokpo TG	목포요금소	木浦料金所				Main Tollgate
3	Muan IC	무안나들목	務安나들목	National Route 1	17.28	23.54
4	Hampyeong JC	함평분기점	咸平分岐點	Muan-Gwangju Expressway Muan International Airport	2.46	26.00		Hampyeong
SA	Hampyeong -cheonji SA	함평천지휴게소	咸平天地休憩所				Mokpo-bound only
5	Hampyeong IC	함평나들목	咸平나들목	National Route 23	7.81	33.81
SA	Hampyeong -cheonji SA	함평천지휴게소	咸平天地休憩所				Seoul-bound only
6	Yeonggwang IC	영광나들목	靈光나들목	National Route 23	24.33	58.14		Yeonggwang
7	Gochang JC	고창분기점	高敞分岐點	Gochang-Damyang Expressway	16.06	74.20		Gochang	Jeonbuk
8	Gochang IC	고창나들목	高敞나들목	Local Route 15	2.74	76.94
SA	Gochang Goindol SA	고창고인돌휴게소	高敞고인돌休憩所
9	Seonunsan IC	선운산나들목	禪雲山나들목	National Route 22 Seonunsa	7.91	84.85
10	Julpo IC	줄포나들목	茁浦나들목	Local Route 710	9.87	94.72		Buan
11	Buan IC	부안나들목	扶安나들목	National Route 30	16.18	110.90
12	W Gimje IC	서김제나들목	西金堤나들목	National Route 29 Saemangeum-Jeonju Expressway (December 2021) Saemangeum	13.93	124.83		Gimje
13	E Gunsan IC	동군산나들목	東群山나들목	National Route 21 National Route 26 National Route 29	12.55	137.38		Gunsan
SA	Gunsan SA	군산휴게소	群山休憩所				Mokpo-bound only
14	Gunsan IC	군산나들목	群山나들목	National Route 21	8.40	145.78
SA	Gunsan SA	군산휴게소	群山休憩所				Seoul-bound only
15	E Seocheon JC	동서천분기점	東舒川分岐點	Seocheon-Gongju Expressway	6.23	152.01		Seocheon	Chungnam
16	Seocheon IC	서천나들목	舒川나들목	National Route 4	8.98	160.99
SA	Seocheon SA	서천휴게소	舒川休憩所
17	Chunjangdae IC	춘장대나들목	春長臺나들목	National Route 21	11.91	172.90
18	Muchangpo IC	무창포나들목	武昌浦나들목	Local Route 606	8.71	181.61		Boryeong
19	Daecheon IC	대천나들목	大川나들목	National Route 36 Daecheon Beach	11.99	193.60
SA	Daecheon SA	대천휴게소	大川休憩所
20	Gwangcheon IC	광천나들목	廣川나들목	Local Route 96	19.72	213.32		Hongseong
SA	Hongseong SA	홍성휴게소	洪城休憩所
21	Hongseong IC	홍성나들목	洪城나들목	National Route 29	10.80	224.12
22	Haemi IC	해미나들목	海美나들목	National Route 45 Haemieupseong	13.68	237.80		Seosan
SA	Seosan SA	서산휴게소	西山休憩所
23	Seosan IC	서산나들목	西山나들목	National Route 32	10.78	248.52
24	Dangjin JC	당진분기점	唐津分岐點	Dangjin-Yeongdeok Expressway	6.56	255.08		Dangjin
25	Dangjin IC	당진나들목	唐津나들목	National Route 34	9.39	264.47
26	Songak IC	송악나들목	松岳나들목	National Route 38 Dangjin Steelworks	8.07	272.54
SA	Haengdam Island SA (Ocean Park Resort)	행담도휴게소	行淡島休憩所				In the Seohae Grand Bridge
BR	Seohae Bridge	서해대교	西海大橋					Pyeongtaek	Gyeonggi
	Anjung JC	안중분기점	安中分岐點	2nd Seohaean Expressway			(December 2023)
27	W Pyeongtaek IC	서평택나들목	西平澤나들목	National Route 82	12.64	285.18
28	W Pyeongtaek JC	서평택분기점	西平澤分岐點	Pyeongtaek–Jecheon Expressway Pyeongtaek-Siheung Expressway	6.53	291.71
29	Baran IC	발안나들목	發安나들목	National Route 39	7.82	299.53		Hwaseong
29-1	Paltan JC	팔탄분기점	八灘分岐點	Seoul 2nd Belt Expressway
SA	Hwaseong SA	화성휴게소	華城休憩所
30	Bibong IC	비봉나들목	飛鳳나들목	National Route 39	13.62	313.15
SA	Maesong SA	매송휴게소	梅松休憩所
31	Maesong IC	매송나들목	梅松나들목	Local Route 84	4.02	317.17
31-1	Palgok JC	팔곡분기점	八谷分岐點	Yeongdong Expressway	3.80	320.97	Mokpo-bound enter only Gangneung-bound exit only	Ansan
32	Ansan JC	안산분기점	安山分岐點	Yeongdong Expressway	5.12	326.09
TG	W. Seoul TG	서서울요금소	西서울料金所				Main Tollgate
33	Jonam JC	조남분기점	鳥南分岐點	Seoul Ring Expressway	2.89	328.98		Siheung
SA	Mokgam SA	목감간이휴게소	牧甘簡易休憩所				Seoul-bound only
34	Mokgam IC	목감나들목	牧甘나들목	National Route 42 Suwon–Munsan Expressway 3rd Gyeongin Highway	3.16	332.14
35	Gwangmyeong Stn. IC	광명역나들목	光明驛나들목	Ori-ro KTX Gwangmyeong Stn.	1.15	333.29		Anyang
36	Iljik JC	일직분기점	日直分岐點	2nd Gyeongin Expressway	2.67	335.96		Gwangmyeong
37	Soha JC	소하분기점	所下分岐點	Suwon-Munsan Expressway Gangnam Beltway			Gangnam-bound only Mokpo-bound only	Geumcheon	Seoul
38	Geumcheon IC	금천나들목	衿川나들목	National Route 1 Doksan Station ( Line 1)	4.20	340.16	Seoul-bound enter only Mokpo-bound exit only
	Seoul	서울 종점	서울 終點	Seobu Urban Expressway	0.65	340.81
Connected directly with Seobu Urban Expressway(서부간선도로)

Events

MBC's Entertainment program, Infinite Challenge held a <Seohaean Expressway Festival> in Haengdam Island Service area in June 2011.