The Shimōsa Plateau is crossed by several short, shallow rivers and two small lakes.
The Kuriyama River (38.8 kilometres (24.1 mi)) flows eastward from the central area of the plateau east of Narita International Airport to the Pacific Ocean.
The shorter Kido River (21.5 kilometres (13.4 mi)) similarly flows eastward and empties into the Pacific Ocean in the city of Sanmu.

Lake Teganuma originally occupied a large area to the north of the plateau, but has narrowed in modern times due to being sealed off from the Tone River and land reclamation projects.
Teganuma historically  covered 10 square kilometres (3.9 sq mi), but after land reclamation now covers 3.7 square kilometres (1.4 sq mi).
Lake Inbanuma was created by the natural damming of a small valley in the Shimōsa Plateau, and originally covered 21.3 square kilometres (8.2 sq mi).
After land reclamation projects, similar to those carried out on Teganuma, it now covers 13.1 square kilometres (5.1 sq mi).
The Shimōsa Plateau is crossed by several short, shallow rivers and two small lakes. The Kuriyama River (38.8 kilometres (24.1 mi)) flows eastward from the central area of the plateau east of Narita International Airport to the Pacific Ocean. The shorter Kido River (21.5 kilometres (13.4 mi)) similarly flows eastward and empties into the Pacific Ocean in the city of Sanmu.
Lake Teganuma originally occupied a large area to the north of the plateau, but has narrowed in modern times due to being sealed off from the Tone River and land reclamation projects. Teganuma historically  covered 10 square kilometres (3.9 sq mi), but after land reclamation now covers 3.7 square kilometres (1.4 sq mi). Lake Inbanuma was created by the natural damming of a small valley in the Shimōsa Plateau, and originally covered 21.3 square kilometres (8.2 sq mi). After land reclamation projects, similar to those carried out on Teganuma, it now covers 13.1 square kilometres (5.1 sq mi).
Shimōsa Plateau