Rosenberg (rō´zənbərg), city (1990 pop. 20,183), Fort Bend co., S Tex., on the Brazos River, in an oil and natural gas area; inc. 1902. Rosenberg and its sister city of Richmond are physically one community. Their economic activities center around plastic products, oil rigs and equipment, food processing, brooms and mops, and engine and motor controls. Rosenberg was founded with the coming of the railroad in 1883 and grew as a farm-marketing and shipping center.