a river in Smolensk Oblast, RSFSR. A right tributary of the Dnieper. Length, 158 km; basin area, 3,300 sq km. The Vop’ flows within the Smolensk Upland; in its upper reaches it flows amid swamps and lower on through a broad valley covered with sparse forests or meadows which are partly swampy. The mean annual discharge at the mouth is about 22 cu m per sec. During the spring, timber is floated down the river. The city of lartsevo is situated on the Vop’.