Boso Peninsula (房総半島 Bôsô-hantô) is a peninsula in Chiba prefecture, Japan, separating Tokyo Bay from the Pacific Ocean. Most of the peninsula is hilly, with some points as high as 400 m above sea level. While the western part of the peninsula is highly urbanized (centered around the city of Kisarazu), the other coastal lowlands and interior river valleys are chiefly used for growing rice.
