罗塞尼亚（Ruthenia）是东欧的一个历史地名，包括现在的白俄罗斯、乌克兰北部、俄罗斯西部、小部分的斯洛伐克东北部和极少部分的波兰东部。

Historical Ruthenia /ruːˈθiːniə/ is a proper geographical exonym for Kievan Rus' and other, more local, historical states. It was applied to the area where Ruthenians lived.

The word Ruthenia originated as a Latin rendering of the region and people known originally as Rus'. Although Rus' is used as the same root word for Russia in the Russian language, the allusion holds a direct link to the former people and state for other Slavs. In European manuscripts dating from the 13th century, "Ruthenia" was used to describe Rus': the wider area occupied by the Ancient Rus' (commonly referred to as Kievan Rus'), most of it known alternatively as the Kingdom of Galicia-Volhynia. After the devastating Mongolian occupation of the main part of Ruthenia, then the incorporation of Ruthenian principalities into the Grand Duchy of Lithuania, then into the Polish–Lithuanian Commonwealth, the territory was converted into the Ruthenian Voivodeship, which existed until the 18th century. A small part of Rus', probably starting from the 8th-9th centuries, historically belonged mainly to the Kingdom of Hungary, with strong cultural ties both to Ruthenia and Hungary, now in Ukraine as a part of Zakarpattia Oblast, with a small part in Slovakia. A territory long disputed as an early part of Hungary, and from the 10th century Ruthenia and Poland, formed the Chervian Towns (hun.: Vörösföldnek, pol.: Grody Czerwieńskie, ukr.:Червенські городи), now mostly in Poland, partly in Ukraine.