Sōja is a city located in Okayama Prefecture, Japan. As of 31 March 2023, the city had an estimated population of 69,428 and a population density of 330 persons per km2. The total area of the city is

The Ibara Line is a Japanese railway line between Sōja Station, Sōja and Kannabe Station, Fukuyama. It is the only railway line operated by the Ibara Railway.