The Kisei Main Line is a railway line that parallels the coastline of the Kii Peninsula in Japan between Mie Prefecture and Wakayama Prefecture. The name takes the kanji characters from the names of the old provinces of Kii (紀伊) and Ise (伊勢).

The Kii Peninsula is the largest peninsula on the island of Honshū in Japan. It is named after the ancient Kii Province. The peninsula has long been a sacred place in Buddhism, Shinto, and Shugendo, and many people would visit from all over Japan as part of the Kumano religious practices.