Rotterdam, town (township), Schenectady county, eastern New York, U.S. It adjoins the city of Schenectady south of the Mohawk River. The Jan Mabie House (1671) recalls early Dutch colonial settlement, as does the town’s official seal, which is identical with that of Rotterdam, Netherlands. Rotterdam was formerly part of Schenectady and was separately incorporated as a town in 1821. Rotterdam Junction, a suburban community in the foothills of the Adirondack Mountains, was, from 1883 to 1931, an important river and rail juncture for Erie Canal shipments. Industries in Rotterdam produce turbines, insulating materials, and other light manufactures. Area 36 square miles (93 square km). Pop. (2000) 28,316; (2010) 29,094.