Inzai city is an important area of northern Chiba prefecture connecting Tokyo and Narita.  It is located 20 kilometers from the central capital at Chiba, 30 to 40 kilometers from central Tokyo and 15 kilometers from Narita. Tone River runs in the north of it. There is Lake Tega in the north-west of it and Lake Imba in the south-east of it. It is surrounded by national forests. The elevation of it is 20 to 30 meters.