Its name refers to the ancient provinces of Mutsu(陸奥) and Dewa(出羽) (or alternatively, the Meiji-era provinces of Rikuzen(陸前) and Uzen(羽前)), although strictly speaking, only the Rikuu East Line connects both areas.
The line was opened in sections between 1913 and 1914. Freight services ceased in 1987, and CTC signalling was commissioned in 1991.
Due to the construction of a tunnel, that is part of Shinjo Sakata Road of National Route 47, the Rikuu West Line has temporarily suspended services since 14 May 2022 until at least 2024~2025, with replacement buses operating in the neighbour towns of stations.[2]