Across the country, 47.3 million people lived in a different house a year earlier and 17.3 million of them lived in a different county within the U.S., according to information the U.S. Census Bureau released today on migration. This translates to an average of about 130,000 people moving every day.

Seven of the top 10 flows of movers were among counties in the Los Angeles and Riverside-San Bernardino, Calif., metropolitan areas. An estimated 44,020 people -- or an average of about 121 per day -- moved from Los Angeles County to San Bernardino County, Calif., which is the largest number of people moving from one county to another in the nation. The rest of the top 10 flows of movers were people moving among counties in the Miami, Phoenix, Detroit and Chicago metro areas.

These findings were released in a series of County-to-County Migration Flow Tables, which come from data collected by the American Community Survey between 2006 and 2010. In the survey, household members were asked where they lived a year ago and responses were combined into a weighted average for the period. The tables give added information on current county of residence, the county of residence one year ago and the estimated number of movers between the counties. Additional tables provide the same information broken down by selected characteristics: age, sex, race or Hispanic origin.

To help users understand and interact with these statistics, the Census Bureau has developed an online mapping tool called Census Flows Mapper. This application allows users to select a county in the U.S. and view the outbound, inbound and net migration flows for that county.  Additionally, users can choose flows based on characteristics such as age, sex, race or Hispanic origin. 

The application also allows users to download data, zoom in and out on the map to an area of interest, view additional statistics of the selected county and save their map as a PDF file.

The largest yearly county-to-county flows originated from Los Angeles County. (Table 1) The characteristics of those movers, however, are different depending on where they moved.  About half (48.9 percent) of those moving to Orange County were between the ages of 18 and 34, compared with 35.7 percent moving to San Bernardino County. San Bernardino had a higher percentage of movers under 18 than Orange County (30.2 percent vs. 19.2 percent).

In terms of race, a similar percentage of whites moved to either San Bernardino County or Orange County from Los Angeles County, while a higher percentage of movers to San Bernardino County rather than Orange County were black (15.0 percent vs. 4.1 percent). Conversely, a higher percentage of movers to Orange County than San Bernardino County were Asian (26.1 percent vs. 9.2 percent).  Whites, blacks and Asians include Hispanics in their percentages.

Hispanics made up 58.1 percent of the population moving from Los Angeles County to San Bernardino County, and 30.8 percent moving to Orange County.

Besides the county-to-county flow tables, there are also tables that contain flows for minor civil divisions for Connecticut, Maine, Massachusetts, Michigan, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont and Wisconsin.

The American Community Survey provides a wide range of important statistics about people and housing for every community across the nation. The results are used by everyone from town and city planners to retailers and homebuilders. The survey is the only source of local estimates for most of the 40 topics it covers, such as education, occupation, language, ancestry and housing costs for even the smallest communities. Ever since Thomas Jefferson directed the first census in 1790, the census has collected detailed characteristics about our nation's people. Questions about jobs and the economy were added 20 years later under James Madison, who said [PDF - 3.9 MB] such information would allow Congress to "adapt the public measures to the particular circumstances of the community," and over the decades allow America "an opportunity of marking the progress of the society."

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