Tsukuba is a city located in the Ibaraki Prefecture of Japan. As of January 1, 2024, the city covers a total area of 283.72 square kilometres (109.54 sq mi) and has an estimated population of 256,526 residing in 121,001 households. The city maintains a population density of approximately 900 persons per km2, with the demographic data indicating that 20.3% of its residents are aged over 65.
The city is notably recognized as the site of Tsukuba Science City. This planned science park was developed during the 1960s to serve as a hub for scientific research and development.