Shinshiro (新城市, Shinshiro-shi) is a city located in Aichi Prefecture, Japan. As of 1 October 2019, the city had an estimated population of 44,581 in 17,691 households, and a population density of 89.3 persons per km. The total area of the city is 499.23 square kilometres (192.75 sq mi).

Shinshiro is located in east-central Aichi Prefecture. Much of the northern and eastern portion of the city area is covered in mountains and forest, and most is within the borders of the Aichi Kōgen Quasi-National Park

The city has a climate characterized by hot and humid summers, and relatively mild winters (Köppen climate classification Cfa). The average annual temperature in Shinshiro is 15.4 °C (59.7 °F). The average annual rainfall is 2,085.5 mm (82.11 in) with July as the wettest month. The temperatures are highest on average in August, at around 26.6 °C (79.9 °F), and lowest in January, at around 4.4 °C (39.9 °F).

Per Japanese census data, the population of Shinshiro has started to decline rapidly over the past 20 years.

Historical population

Year	Pop.	±%
1960	59,891	—
1970	54,042	−9.8%
1980	54,239	+0.4%
1990	54,583	+0.6%
2000	53,603	−1.8%
2010	49,871	−7.0%

Aichi Prefecture

• Toyohashi
• Okazaki
• Toyokawa
• Toyota
• Kitashitara District, Tōei
• Kitashitara District, Shitara

Shizuoka Prefecture

• Hamamatsu (Hamana-ku, Tenryū-ku)

The area of present-day Shinshiro was part of the territories of the Okudaira clan, the predecessors of the Matsudaira clan and Tokugawa clan during the Sengoku period. Their stronghold, Nagashino Castle in what is now the northern part of Shinshiro, was the site of the Battle of Nagashino, between the forces of Oda Nobunaga and the Takeda clan.

Noda Castle, at which Takeda Shingen was wounded at the Siege of Noda was also located within the borders of Shinshiro.

During the Edo period, most of the area was tenryō territory ruled directly by the Tokugawa shogunate through hatamoto administrators.

After the start of the Meiji period, Shinshiro Town in Minamishitara District, Aichi Prefecture was proclaimed on 1 October 1889 with the establishment of the modern municipalities system.

The area of the town expanded through annexation of neighboring villages in 1955 and 1956. The city of Shinshiro was proclaimed on 1 November 1958.

On 1 October 2005, the town of Hōrai, and the village of Tsukude (both from Minamishitara District) were merged into Shinshiro. The city of Shinshiro now covers all of former Minamishitara District.

Shinshiro has a mayor-council form of government with a directly elected mayor and a unicameral city legislature of 18 members. The city contributes one member to the Aichi Prefectural Assembly. In terms of national politics, the city is part of Aichi District 14 of the lower house of the Diet of Japan.

Shinshiro is a regional commercial center, with the economy concentrated on agriculture, especially chicken farming, and light manufacturing.

• Aichi Shinshiro Otani University

now closed

Shinshiro has 13 public elementary schools and six public junior high schools operated by the city government, and one public high school operated by the Aichi Prefectural Board of Education. There is also one private high school.

Central Japan Railway Company

• Iida Line: - Nodajō - Shinshiro - Higashi-Shimmachi - Chausuyama - Mikawa-Tōgō - Ōmi - Torii - Nagashinojō - Hon-Nagashino - Mikawa-Ōno - Yuya-Onsen - Mikawa-Makihara - Kakidaira - Mikawa-Kawai - Ikeba -

• Tōmei Expressway
• New Tōmei Expressway

• National Route 151
• National Route 257
• National Route 301
• National Route 420

• Neuchatel, Switzerland
• New Castle, Pennsylvania, United States, since 12 November 1998
• Newcastle upon Tyne, England

• Taketoyo, Aichi Prefecture, since 1984

Shinshiro was part of the 1998 summit of worldwide cities named "New Castle" with:

Neuburg an der Donau, Germany Neuchâtel, Switzerland Neufchâteau, Vosges, France New Castle, Delaware, United States New Castle, Indiana, United States

New Castle, Pennsylvania, United States Newcastle-under-Lyme, England Newcastle upon Tyne, England Newcastle, KwaZulu-Natal, South Africa

• Atera Seven Falls
• Fuka-ji
• Hōraisan Tōshō-gū shrine
• Mount Hōraiji
• Site of Nagashino Castle
• Narusawa Waterfall
• Site of Noda Castle
• Sakurabuchi Park
• Thousand Rice Paddies of Yotsuya (Yotsuya Senmaida)
• Yuya Onsen

• 
  Sakurabuchi Park
• 
  Mount Hōraiji
• 
  Mount Hōraiji (Niōmon)
• 
  Hōraisan Tōshō-gū
• 
  Hōrai-ji
• 
  Site of former Nagashino Castle
• 
  Atera Seven Falls
• 
  Narusawa Waterfall
• 
  Thousand Rice Paddies of Yotsuya (Yotsuya Senmaida)
• 
  Yuya Onsen
• 
  Fuka-ji

• Akihiro Ota, politician

• Official website (in Japanese)
• Shinshiro City official website (in English)