County-to-county record layouts - Required for .dat files 2010-2011 DOC 2009-2010 DOC 2008-2009 DOC 2007-2008 DOC 2006-2007 DOC 2005-2006 2004-2005 U.S. Population Migration Data: Strengths and Limitations DOC Return to Migration Data Downloads Return to County to County Migration Database Files Return to State to State Migration Database Files