The Tenryū Hamanako Line , or Tenhama Line for short, is a Japanese railway line in Shizuoka Prefecture, paralleling the north coast of Lake Hamana between Kakegawa Station in Kakegawa and Shinjohara Station in Kosai. This is the only railway line of Tenryū Hamanako Railroad .

Shizuoka Prefecture is a prefecture of Japan located in the Chūbu region of Honshu. As of September 2023, Shizuoka Prefecture has a population of 3,555,818 and has a geographic area of 7,777.42 km2 (3,002.88 sq mi). Shizuoka Prefecture borders Kanagawa Prefecture to the east, Yamanashi Prefecture to the northeast, Nagano Prefecture to the north, and Aichi Prefecture to the west.