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

This article contains a bulleted list or table of intersections which should be presented in a properly formatted junction table. Please consult this guideline for information on how to create one. Please improve this article if you can. (November 2021)

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