Rudnia may refer to the following places:
;Poland
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Rudnia, Gmina Czarna Białostocka in Podlaskie Voivodeship, north-east Poland
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Rudnia, Gmina Michałowo in Podlaskie Voivodeship, north-east Poland
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Rudnia, Warmian-Masurian Voivodeship, north Poland
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Rudnia River, a tributary in Poland of the
Narew
The Narew (; be, Нараў, translit=Naraŭ; or ; Sudovian: ''Naura''; Old German: ''Nare''; uk, Нарва, translit=Narva) is a 499-kilometre (310 mi) river primarily in north-eastern Poland, which is also a tributary of the river Vis ...
;Lithuania
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Rudnia (Kaniava), a village in Kaniava eldership, Varėna district municipality, Alytus County, Lithuania
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