is a city located in Ibaraki Prefecture, Japan. , the city had an estimated population of 75,212 in 33,421 households and a population density of 958 persons per km<sup>2</sup>. The percentage of the population aged over 65 was 31.1% in July 2020. The total area of the city is .
Ryà «gasaki is located in southern Ibaraki Prefecture, in the low-lying flatlands south of Lake Kasumigaura. The Kokai River runs through the western part of the city, and the basin is dotted with tributaries and lakes. Lake Ushiku, despite its name, is entirely within the city of Ryà «gasaki.
Ibaraki Prefecture
Ryà «gasaki has a Humid continental climate (Köppen Cfa) characterized by warm summers and cool winters with light snowfall. The average annual temperature in Ryà «gasaki is . The average annual rainfall is with October 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 Ryà «gasaki has recently plateaued after several decades of growth.
The name "Ryà «gasaki" can be traced back to 1182 when the samurai clan ruling the territory adopted "Ryà «gasaki" as their family name. The northern half of the city was an exclave of Sendai Domain during the Edo period, the region joined in 1869 before merging with Ibaraki Prefecture in 1875. The southern portion of the city was part of Kitasà Âma District in Shimà Âsa Province, as the boundary between Shimà Âsa and Hitachi Province had been established in the Nara period as the Tone River. However, by the Meiji period, the course of the river had shifted, leaving the area of present-day southern Ryà «gasaki on the northern bank of the river. This area was transferred to Ibaraki Prefecture in 1875
The town of Ryà «gasaki was created with the establishment of the modern municipalities system on April 1, 1889.
The city was formed on March 20, 1954, when the aforementioned town merged with: , , , , and . In February 1955, the city grew to its present size when a proportion of merged with the city.
In 1974, the city adopted the Swan, the Pinus, and Platycodon grandiflorus as its city symbols for bird, tree and flower respectively.
Ryà «gasaki has a mayor-council form of government with a directly elected mayor and a unicameral city council of 22 members. Ryà «gasaki, together with neighboring Tone, contributes two members to the Ibaraki Prefectural Assembly. In terms of national politics, the city is part of Ibaraki 3rd district of the lower house of the Diet of Japan.
The 20th and current mayor is Isamu Hagiwara, who assumed the position on January 18, 2022. Issei Nakayama was the seventeenth to nineteenth mayor, beginning in January 2010.
New Central Airlines, a commuter airline, is headquartered in the city, on the grounds of Ryà «gasaki Airfield, although no commercial flights are scheduled from the city.
JR East â Jà Âban Line
Kantà  Railway - Ryà «gasaki Line