Brimfield Township is located in the Southwest quadrant of Portage County, Ohio. It is bordered by the city of Kent to the north, Rootstown Township to the east, Suffield Township to the south, and by the city of Tallmadge in Summit County to the west. The township has an area of twenty-two and one half square miles.

The Township has access to an excellent transportation system with two interstate highway exchanges on I-76 located within the township, State Route 43 traversing in a north/south direction and State Route 261 located just north of the Township. The Township also contains a reasonably developed network of Local Township and county roads.