Although the 2010 federal census shows Boston went above 600,000 residents for the first time since 1970, neighborhood-level maps show large parts of Dorchester, Mattapan and Roslindale lost population over the past 10 years. See for yourself on this interactive New York Times map.
One example: Census Tract 101001, roughly centered on Cummins Highway between Harvard Street and Blue Hill Avenue in Mattapan, saw a 9.2% drop in population, to 5,480. Neighboring Tract 101002, from Blue Hill Avenue to Morton Street and bordered on the south by River Street, decreased 7.9%. Tract 11103, which includes the area around Forest Hills station in both JP and Roslindale, dropped 12%, to 5,460.
In contrast, the South Boston waterfront and the areas around Northeastern University exploded in population. Census Tract 612, bounded roughly by Summer Street, Fort Point Channel, I-93 and Old Colony Avenue, for example, saw a 70% increase, to 3,240 people. Neighboring Tract 606, centered on D Street, saw an 81% increase, to 2,357.
Downtown saw similar increases. Tract 70101, across Fort Point Channel from 612 and including Chinatown, increased 86%, to 5,902; Tract 303, centered on State Street (and including part of the North End), went up a more modest 19%, to 4,872.
Roxbury in general also saw population increases. Beacon Hill went up in population, while the Back Bay dropped.
In Dorchester, only Lower Mills, Colombia Point and part of Uphams Corner saw increases.
