In many cities, the population grows during the workday. Commuting into and out of a city allows workers to live in residential areas, which may better fit their housing needs and family situation. However, there may also be instances where commuting into or out of a city is less than desirable. This study investigates the social and economic characteristics of daytime urban commuters for 20 U.S. cities using restricted access microdata from the 5-year 2009-2013 American Community Survey (ACS).