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National Route 42
国道42号
Route information
Length	504.6 km[1] (313.5 mi)
Existed	1 April 1959–present
Major junctions
East end	National Route 1 in Hamamatsu
West end	National Route 24 in Wakayama
Location
Country	Japan
Highway system
National highways of Japan Expressways of Japan
← National Route 41 → National Route 43

National Route 42 (国道42号, Kokudō yonjūni-gō), also called Kumano Kaidō or Tropical Route is a national highway connecting Hamamatsu, Shizuoka and Wakayama, Wakayama in Japan. Part of the route requires crossing Ise Bay on the Ise-wan Ferry.^[2][3] It is the 8th longest national highway in Japan.

The total length on the main road is 487.2km(307.2 miles). However, by factoring in the overlapped section (33.4km/20.8 miles) and the sea crossing(19.8km/12.3 miles)the total distance becomes 540.3km(335.7miles).^[4] At the origin Hamamatsu, the route starts overlapped with Route 1 and, is a junction to route 257 and 300. The route passes though the cities of Tahara, Toba, Ise, Matsusaka, Owase, Kumano, Shingū, Tanabe, and Gobō. At the terminus Wakayama, there is a junction with national route 24 and 26.

• From the origin to Kosai: Route 1
• From Tahara to Toba (Ferry crossing section): Route 259
• From Toba to Ise: Route 167
• From Ise to Matsusaka : Route 23
• From Tanabe to Minabe: Route 424

Route 42 was originally designated in January 1945 as a section of Route 41 (the Kumano Highway), which ran to Tokyo. This ran concurrent with Route 1 (now Route 1/Route 23). On 18 May 1953 Route 41 was classified as a Class 2 highway and redesignated as Route 170, which was later redesignated as Route 42 when the route was promoted to a Class 1 highway. On 1 April 1965, the classification of Class 1 and Class 2 was discontinued, redesignating it as General National Route 42.

On 1 April 1993, the highway was changed by removing the section of Tsu-Matsusaka and adding the Hamamatsu - Matsusaka. This was part of the plan to connect the Atsumi Peninsula, though the Kii Peninsula, Shikoku, Kyushu and terminating at Okinawa.^[5] This plan is called the Japan Sea National Land Axis Plan.^[6]

Shizuoka Prefecture

• Hamana Bypass (浜名バイパス)^[7]
  • Hamamatsu - Kosai

Aichi Prefecture

• Sanen Ise Access Road (三遠伊勢連絡道路)^[8] - Planning Stage
  • Hamamatsu - Ise (Mie Prefecture)

Mie Prefecture

• Matsusaka - Taki Bypass (松阪多気バイパス)^[9]
  • Matsusaka - Taki
• Kumano - Owase Road (熊野尾鷲道路)^[10]
  • Owase - Kumano
• Odomari Bypass (大泊バイパス)^[11]
  • Kumano
• Kumano Road (熊野道路)^[12]
  • Kumanoo
• Kiho Bypass (紀宝バイパス)^[13]
  • Kiho - Shingu
• Shingu - Kiho Road (新宮紀宝道路)^[14]
  • Kiho - Shingu

Wakayama Prefecture

• Nachikatsuura - Shingu Road (那智勝浦新宮道路)^[15]
  • Shingu - Nachikatsuura
• Kushimoto - Taiji Road (串本太地道路)^[16]
  • Taiji - Kushimoto
• Susami - Kushimoto Road (すさみ串本道路)^[17]
  • Kushimoto - Susami
• Yuasa - Gobo Road (湯浅御坊道路) - Toll Road^[18]
  • Gobo - Yuasa
• Hiki River Road (日置川道路)^[19]
  • Sasumi - Shirahama
• Tanabe Bypass (田辺バイパス)^[20]
  • Kamitonda - Tanabe
• West Tanabe Bypass (田辺西バイパス)^[20]
  • Tanabe
• Yura Bypass (由良バイパス)
  • Yura - Hirogawa
• Arida Bypass (有田バイパス)
  • Arida
• Shimizu Widening (冷水拡幅) - Partially Under Construction^[21]
  • Kainan
• Arita - Kainan Road (有田海南道路) - Partially Under Construction^[21]
  • Arida - Kainan
• Kainan Bypass (海南バイパス)
  • Kainan

Prefecture	Location	km	mi	Destinations	Notes
Shizuoka	Hamamatsu			National Route 257 / National Route 301 – Takayama, Toyota National Route 1 – Osaka, Tokyo	Overlapping section of National Route 1
	Kosai			National Route 257 / National Route 301 – Takayama, Toyota National Route 1 – Osaka, Tokyo	End of overlapping section of National Route 1
Aichi	Tahara			Aichi Prefectural Route 28 – Takahara
				Aichi Prefectural Route 2 – Toyohashi
				National Route 259 – Toba,Toyohashi	Overlapping section with National Route 259
Ise Wan	Tahara - Toba			Ise Wan Ferry
Mie	Toba			National Route 167 – Shima,Ise	Overlapping section with National Route 167
				National Route 167 – Shima,Ise	End of overlapping section for National Route 167
	Ise			Ise-Futami-toba Line - Ise
				National Route 23 – Toyohashi,Ise
	Meiwa			Mie Prefectural Route 60 – Ise, Matsusaka
	Matsusaka			Mie Prefectural Route 59 – Matsusaka
				National Route 23 – Ise, Toyohashi	End of overlapping section with National Route 23
				Mie Prefectural Route 60 – Ise, Matsusaka	On the Matsusaka - Taki Bypass
				Mie Prefectural Route 37 – Toba, Matsusaka	On the Matsusaka - Taki Bypass
				Mie Prefectural Route 59 – Matsusaka	On the Matsusaka - Taki Bypass
				Mie Prefectural Route 59 – Matsusaka	On the Matsusaka - Taki Bypass
				Mie Prefectural Route 59 – Matsusaka
				Mie Prefectural Route 59 – Matsusaka
	Taki			Mie Prefectural Route 13 – Ise,Taki
				Ise Expressway - Ise,Tsu Kisei Expressway - Taki,Owase	Seiwa-Taki Interchange
				National Route 368 – Iga, Taki
	Odai			Mie Prefectural Route 46 – Minamiise,Odai
				Mie Prefectural Route 31 – Odai
				Kisei Expressway - Taki,Owase	Omiya - Odai Interchange
	Taiki			Mie Prefectural Route 38 – Taiki,Ise
				Mie Prefectural Route 33 – Taiki,Ise
				Mie Prefectural Route 68– Taiki	Connecting to Kisei Expressway - Taki,Owase
	Kihoku			National Route 260 – Kihoku, Shima
				National Route 422 – Otsu, Kihoku
				National Route 422 – Otsu, Kihoku
				Kisei Expressway - Taki,Owase	Miyama Interchange
	Owase			National Route 425 – Owase, Gobo
				National Route 311 – Owase, Kamitonda
				Mie Prefectural Route 70 – Owase
				Mie Prefectural Route 70 – Owase	On the Kumano Owase Road (Bypass)
	Kumano			National Route 309 – Osaka, Kumano
				National Route 311 – Owase, Kamitonda	Overlapping section with National Route 311
				Mie Prefectural Route 34 – Kumano
				National Route 311 – Owase, Kamitonda	End of overlapping section of National Route 311
	Mihama			Mie, Wakayama Prefectural Route 52 – Mihama,Kitayama
				Mie Prefectural Route 62 – Mihama,Kumano
	Kiho			Mie Prefectural Route 35 – KIho,Mihama	On Kiho Bypass
Wakayama	Shingu			Wakayama Prefectural Route 42 – Shingu
				National Route 168 – Shingu, Hirakata
	Nachikatsuura			Wakayama Prefectural Route 43 – Nachikatsuura,Kozagawa
				Wakayama Prefectural Route 46 – Nachikatsuura	Entrance of Bypass road
				Wakayama Prefectural Route 46 – Nachikatsuura
				Wakayama Prefectural Route 46 – Nachikatsuura
				Wakayama Prefectural Route 45 – Nachikatsuura,Tanabe
	Kushimoto			Wakayama Prefectural Route 38 – Kushimoto,Susami
				Wakayama Prefectural Route 41 – Kushimoto
				Wakayama Prefectural Route 41 – Kushimoto
				National Route 371 – Kushimoto, Kawachinagano
				Wakayama Prefectural Route 39 – Kushimoto,Kozagawa
	Susami			Wakayama Prefectural Route 36 – Susami,Kamitonda
				Wakayama Prefectural Route 38 – Kushimoto,Susami
	Shirahama			Wakayama Prefectural Route 37 – Shirahama,Tanabe
				Wakayama Prefectural Route 34 – Shirahama
	Kamitonda			Wakayama Prefectural Route 31 – Shirahama,Tanabe
				National Route 311 – Owase, Kamitonda
	Tanabe			Wakayama Prefectural Route 33 – Tanabe Wakayama Prefectural Route 31 – Shirahama,Tanabe	To Nanki-Shirahama Airport
				Wakayama Prefectural Route 29 – Tanabe
				Wakayama Prefectural Route 208 – Tanabe
				Hanwa Expressway Kisei Expressway	Nanki Tanabe Interchange
				National Route 424 – Tanabe, Kinokawa	Overlapping section with National Route 424
	Minabe			National Route 424 – Tanabe, Kinokawa	End of overlapping section with National Route 424
	Inami			Wakayama Prefectural Route 28 – Inami
	Gobo			National Route 425 – Owase, Gobo
				Wakayama Prefectural Route 25 – Gobo,Hidakagawa
				Wakayama Prefectural Route 26 – Gobo,Hidakagawa
				Wakayama Prefectural Route 24 – Gobo,Hidakagawa
	Hidaka			Wakayama Prefectural Route 27 – Hidaka,Inami
				Wakayama Prefectural Route 23 – Hidaka,Yuasa
	Yura			Wakayama Prefectural Route 23 – Hidaka,Yuasa
				Wakayama Prefectural Route 23 – Hidaka,Yuasa
	Hirogawa			Wakayama Prefectural Route 27 – Hidaka,Inami
				Hanwa Expressway	Hirokawa Interchange
	Yuasa			Wakayama Prefectural Route 23 – Hidaka,Yuasa
	Aridagawa			Hanwa Expressway	Arida Interchange
				Wakayama Prefectural Route 22 – Aridagawa
	Arida			Wakayama Prefectural Route 20 – Arida,Yuasa
				Wakayama Prefectural Route 20 – Arida,Yuasa
				National Route 480 – Arida, Izumiotsu
	Kainan			Hanwa Expressway	Kainan Interchange
				National Route 370 – Kainan, Nara
				Wakayama Prefectural Route 9 – Kainan,Iwade
	Wakayama			Wakayama Prefectural Route 13 – Wakayama,Hashimoto
				National Route 26 – Wakayama, Osaka National Route 24 – Wakayama, Kyoto
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus       Incomplete access       Route transition