Seya Ward is located in eastern Kanagawa Prefecture, and on the northwestern borders of the city of Yokohama.

At times, Seya was administered by Totsuka-juku, Fujisawa-shuku, and towards the Bakumatsu period came under the control of the Nirayama daikansho .

On April 1, 1939, Seya was annexed by the neighboring city of Yokohama, becoming part of Totsuka Ward.

During World War II, Seya hosted numerous military facilities, including munitions plants and training grounds.

In a major administrative reorganization of October 1, 1969, Totsuka-ku was divided, and Seya emerged as an independent ward within Yokohama.

Seya Ward is largely a regional commercial center and bedroom community for central Yokohama and Tokyo.