The County-to-County Migration Flows Tables, which use data collected by the American Community Survey between 2007 and 2011, show how many Iowa residents move from one specific county to another during the course of a year.
These statistics show how many of the population age 1 and older move in a year across county lines or from abroad. The county-to-county migration flows tables show this information cross-tabulated by educational attainment, individual and household income.
Reports can be found on the Iowa State Data Center website. Select the "Data" tab at the top of the page. Then use the navigation box on the left-hand side of this page and select "County-to-County Migration".