Since 1950, the beginning of the decade of the expansion of the national highway system at the hands of the Eisenhower administration, city centers throughout the United States saw huge numbers of people depart for the suburbs.  Nowhere was this more starkly evident than in the Rustbelt and Northeast, areas which were hammered by the loss of manufacturing jobs.

One example of the dramatic population changes during the 20th century is St. Louis, which was the 3rd most populous city in America in 1920 but had shrunken down to a paltry 319,000 residents by 2010. Despite these glaring losses to city centers, most of the metropolitan areas around these cities actually increased in population during the same period, evidence of the general shift to the suburbs after 1950.

Cities ranked by population in 2010 with greater than 20% population decrease since 1950: