Situated in the southeast corner of Saitama Prefecture, Sōka is surrounded to the east by the cities of Yashio, Misato and Yoshikawa, and to the west by Kawaguchi. To the north is Koshigaya City and to the south Adachi City of Metropolitan Tokyo. It is approximately 30 kilometers away from Tokyo.
Sōka, once a peaceful agricultural area surrounded by water and greenery, lies in the Nakagawa-ayase basin, an area referred to as the Nakagawa-teichi district. This alluvial plain spreads over the central part of the Kanto Plain. As a result of urbanization, the once abundant greenery and clean water was adversely affected. Now, Sōka is promoting a "town of greenery and water based on history and the natural features of the area". Creation of areas of greenery reflecting the changes of the four seasons, and the restoration of waterways and environs is being advanced.
On November 1, 1958 Soka was incorporated as a city with a population of 34,878. Following this, rapid population expansion and urbanization took hold due to strong economic growth which was fueled by its proximity to Tokyo.