is a city in Aichi Prefecture, Japan. , the city had an estimated population of 80,063 in 32,800 households, and a population density of 1,407 persons per km<sup>2</sup>. The total area of the city is .
Gamagà Âri is situated on the coast of Mikawa Bay on the Pacific Ocean in southeastern Aichi Prefecture. Sheltered by Chita Peninsula and Atsumi Peninsula, the climate is mild, and parts of the city is within the borders of the Mikawa Wan 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 Gamagà Âri is . The average annual rainfall is with September as the wettest month. The temperatures are highest on average in August, at around , and lowest in January, at around .
Per Japanese census data, the population of Gamagà Âri has been relatively steady over the past 30 years.
Records of place names in present-day Gamagà Âri have been found from the Nara period.
The area was divided into several shà Âen during the Heian period, largely under the control of the Udono clan.
During the Edo period, most of the area was tenryà  territory ruled directly by the Tokugawa shogunate through hatamoto administrators, with portions controlled by Yoshida Domain and Okazaki Domain.
After the start of the Meiji period, Gamagà Âri Village in Hoi District, Aichi Prefecture was proclaimed on October 1, 1889. Gamagà Âri was elevated to town status on October 6, 1891.
The area of the town expanded through annexation of the neighboring villages of Toyooka, Kaminogo and Shizusato on July 4, 1906.
The town escaped damage in World War II, but the 1945 Mikawa earthquake caused considerable damage to parts of Gamagà Âri.
The city of Gamagà Âri was proclaimed on April 1, 1954, when the town of Gamagà Âri merged with the neighboring town of Miya and village of Shiotsu.
The village of Otsuka joined Gamagà Âri on October 1, 1956, followed by Katahara on April 1, 1962, and Nishiura on April 1, 1963.
Gamagà Âri has a mayor-council form of government with a directly elected mayor and a unicameral city legislature of 20 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.
Gamagà Âri is a regional commercial center and fishing port, with a mixed economy of light manufacturing and agriculture. Gamagà Âri is also noted for its production of hothouse oranges. Companies headquartered in the city include:
As part of Mikawa Wan Quasi-National Park with numerous scenic offshore islands, Gamagà Âri is noted for marine sports. There are also several hot spring resorts within the city limits. The Gamagà Âri Matsuri, held in late July features a fireworks display, and the local festival of former Miya village held in October features an event where mikoshi are carried into the sea. The city is also home to the Lagunasia amusement park and Spa Nishiura Motor Park racetrack.
The small fishing community of Nishiura is noted for its onsen (hot spring resorts), some of which are located near its beach front. The area is famous for the medicinal properties of its water and a number of hotels have sprung up to accommodate the tourists visiting these spas.