Tsu is the capital city of Mie Prefecture, Japan. As of 31 July 2021, the city had an estimated population of 274,879 in 127,273 households and a population density of 390 persons per km2. The total area of the city is 711.11 square kilometres (274.56 sq mi). Although the second largest city in the prefecture in terms of population, its designation as the prefectural capital and its holding of a large concentration of national government offices and educational facilities make the city the administrative and educational center of Mie Prefecture.

Mie Prefecture is a prefecture of Japan located in the Kansai region of Honshu. Mie Prefecture has a population of 1,781,948 and has a geographic area of 5,774 square kilometers (2,229 sq mi). Mie Prefecture is bordered by Gifu Prefecture to the north, Shiga Prefecture and Kyoto Prefecture to the northwest, Nara Prefecture to the west, Wakayama Prefecture to the southwest, and Aichi Prefecture to the east.