Upon the merging of the canton of Baden into Aargau in 1803, the district gained the municipalities of Würenlingen, Bellikon, Künten, Remetschwil, Stetten, Mellingen, Wohlenschwil and Mägenwil (from neighbouring districts of the canton of Baden) but had to give up Hüttikon, Oetwil an der Limmat, Dietikon and Schlieren to the Canton of Zurich.