Spreitenbach (High Alemannic: Spräitebach) is a municipality in the district of Baden in the canton of Aargau in Switzerland, located in the Limmat Valley (German: Limmattal). It lies southeast of the district center, directly on the border with the canton of Zurich.It is one of the smallest cities in Switzerland. In Switzerland, a city needs a population of 10,000 or more to be considered as a city.