Composed of a mix of bedroom communities, mid-sized industrial cities and (formerly) rural towns, the South Shore is known for being a popular destination of those who have engaged in white flight from the city of Boston, particularly Irish-Americans. Today, Massachusetts' heaviest concentration of residents descended from Ireland is on the South Shore., and six of the United States' ten most Irish towns are located on the South Shore. For this reason the South Shore is sometimes jocularly known as the "Irish Riviera".
Local residents disagree whether the South Shore extends north, south and inland from this core. Some would consider three communities north and northwest of the above list, members of the Boston-centered Inner Core Committee, to be "South Shore": Milton, Quincy and Randolph.
Some towns and cities inland from Pembroke and south of Duxbury are also often included in definitions of the South Shore. These communities, chiefly located in Plymouth County, include:
Some maintain that the South Shore, and the "Irish Riviera," include all or parts of Cape Cod; still others say the Plymouth area is part of Cape Cod, not the South Shore. In some cases, the competing definitions depend on whether Cape Cod Bay is considered to be part of Massachusetts Bay.
The South Shore is distinct from Massachusetts' similarly named South Coast, a neighboring region to the southwest.