Migration/Geographic Mobility

The U.S. Census Bureau has been releasing county-to-county and county/minor civil division (MCD)-to-county/MCD migration flow estimates based on the American Community Survey (ACS) since 2012. The first table package used data collected from 2005 through 2009 that composed the first ACS 5-year dataset. For sequential 5-year ACS datasets, tables were crossed by selected characteristics. The 2008-2012 release was the first time flows from Puerto Rico municipios to U.S. counties were included. Flows between metropolitan statistical areas (MSAs) were introduced with the 2009-2013 dataset. In addition, the county-to-county flows going back to 2006-2010 dataset are available through the Census Flows Mapper. As of 2016, all ACS migration flows data for counties, MCDs, and MSAs were made available in the Census application programming interface (API) through the Census Developers site.