BARBY, a town of Germany, in the kingdom of Prussia, on the left bank of the Elbe, 82 m. S.W. of Berlin on the direct railway to Cassel. Pop. (1900) 5136. It has two evangelical churches and a seminary for school teachers, which is housed in the former castle of the lords of Barby. The industries are mainly agricultural, but there are sugar factories and breweries. Here from 1749 to 1809 was a settlement of the Herrnhut evangelical brotherhood.