The area had been developed extensively since the 1950s to support demand for housing around rapidly expanding Tokyo and Yokohama. The hills are now mostly a patchwork of new residential suburbs and low, forested hills and pockets of remaining farmland.
Since the 1950s, the area has undergone significant development to accommodate the increasing demand for housing in the vicinity of rapidly growing Tokyo and Yokohama. Today, the hills are predominantly composed of newly constructed residential areas and low-lying wooded hills, interspersed with remaining agricultural land.