Black Ruthenia, Black Rus' or Black Russia are variant conventional terms used for a region around Navahrudak (Novgorodok), in the western part of contemporary Belarus on the upper reaches of the Neman River for the time period between the 13th and 14th centuries. The phrase of "coloured" Ruś first appeared in Western European sources circa 1360, but referring to Red Ruthenia (in modern Ukraine). Early Russian sources do not use the term "Black Ruś". The name "Black Ruthenia" appears primarily in historical writings from the 18th century.
Besides Navahrudak, other important cities of the Black Ruthenian region included Hrodna (Grodno), Slonim, Volkovysk (Vaŭkavysk), Lida, and Niasvizh.