Suwa Domain was a feudal domain under the Tokugawa shogunate of Edo period Japan. It was located in Shinano Province, Honshū. The domain was centered at Takashima Castle, located in what is now part of the town of Suwa in Nagano Prefecture. It was also known as Takashima Domain .

Takashima Castle is a Japanese castle located in Suwa, central Nagano Prefecture, Japan. At the end of the Edo period, Takashima Castle was home to the Suwa clan, daimyō of Takashima Domain. The castle is also known as ’The Floating Castle of Suwa’’’ or Shimazaki Castle