Distance average person lives from mother Credit: The Health and Retirement Study, 2008

Families traveling from far-flung places, returning home for the holidays. That image of an American Christmas fits the perception of Americans as rootless, constantly on the move to seek opportunity even if it means leaving family behind.

Yet that picture masks a key fact about the geography of family in the United States: The typical adult lives only 18 miles from his or her mother, according to an Upshot analysis of data from a comprehensive survey of older Americans. Over the last few decades, Americans have become less mobile, and most adults – especially those with less education or lower incomes — do not venture far from their hometowns.

The data reveal a country of close-knit families, with members of multiple generations leaning on one another for financial and practical support. The trend will continue, social scientists say, as baby boomers need more care in […]