A number of factors affected Watertown's progress. The economic center of the country kept moving west following development of the frontier and a shift of population into the Midwest. As Chicago boomed, it attracted many of the younger people from upstate New York for its business and professional opportunities. In the mid-20th century, industrial technology shifted and jobs changed. In the restructuring of railroads and deindustrialization that took place in the mid- and late 20th century, Watertown suffered economic and population declines.