Historical region, northwestern Ukraine.
Located around the headstreams of the Bug rivers, it originally was a Russian principality (10th–14th century), west of {{link=Kiev">Kiev . In the 14th century it became part of the Grand Duchy of Lithuania but was ruled largely by its own aristocracy. It passed to Poland in 1569. In 1793 it was transferred to Russia under the second partition of Poland. The Treaty of Riga (1921) divided it between Poland and the U.S.S.R. The U.S.S.R. took the Polish section in 1939 and made it part of the Ukrainian S.S.R. after World War II.