Massachusetts was founded by the migration of English religious groups to its shores, and for over a century their descendants dominated all activity in the state. The first non-English to enter Massachusetts in significant numbers were the Irish, who migrated in vast numbers during the 1840s and 1850s. By 1860, one-third of Boston's population was Irish, while nearly one-fourth of Middlesex and Norfolk counties and one-fifth of the inhabitants of Berkshire, Bristol, Essex, and Hampden counties were Irish-born. Other ethnic groups—such as the Scottish, Welsh, Germans, and Poles—were also entering the state at this time, but their numbers were small by comparison. During the late 1880s and 1890s, another wave of immigrants—from Portugal, Spain, Italy, Russia, and Greece—arrived. Irish and Italians continued to enter the state during the 20th century.
A slow but steady migration from Massachusetts farm communities began during the mid–l700s and continued well into the 1800s. The first wave of farmers resettled in northern Connecticut, Vermont, New Hampshire, and Maine. Later farmers moved to New York's Mohawk Valley, Ohio, and points farther west. Out-migration has continued into recent times: from 1970 to 1990, Massachusetts lost nearly 400,000 residents in net migration to other states but experienced an overall net increase from migration of 59,000 due to migration from abroad. Between 1990 and 1998, the state had a net loss of 237,000 in domestic migration and a net gain of 135,000 in international migration. In 1996, Massachusetts's foreign-born population numbered 591,000, or nearly 10% of the state's total population. In 1998, 15,869 foreign immigrants arrived in Massachusetts, the 8th-highest total of any state for that year. Between 1990 and 1998, the state's overall population increased 2.2%. In the period 1995–2000, 446,849 people moved into the state and 501,557 moved out, for a net loss of 54,708, 14,434 of whom were age 65 or over and many of whom moved to Florida.
The only significant migration from other areas of the United States to Massachusetts has been the influx of southern blacks since World War II. According to census estimates, Massachusetts gained 84,000 blacks between 1940 and 1975; between 1990 and 1998, the black population grew from 300,000 to 395,000 persons, mostly in the Boston area.