Mount Hiyori (日和山, Hiyoriyama) located in Sendai, Miyagi Prefecture, is Japan's lowest mountain.

At one time, it was recognized as the lowest mountain in Japan as a mountain on the topographic map of the Geospatial Information Authority of Japan, but that position was ceded when Mount Tenpō (Osaka City) was re-listed.

For this reason, the word "Gan-so" (元祖, meaning "original") was added to the information signboard at the summit that read "the lowest mountain in Japan".

However, it was reported on April 9, 2014, that it was recognized as a mountain with an altitude of 3 metres (9.8 ft) in a survey by the Geospatial Information Authority of Japan.

[2] As a result, it fell below Mount Tenpō for the first time in 18 years and again became the lowest mountain in Japan.