This article shows U.S. Census totals for Suffolk County, Massachusetts, broken down by municipality, from 1900 to 2010.
Like most areas of New England, Suffolk County is (and has been at all times since well before the 20th century) entirely divided into incorporated municipalities. There is no unincorporated territory. For any census, adding up the totals for each municipality should yield the county total.
There are two types of municipalities in Massachusetts, towns and cities. The tables below differentiate between towns and cities.
For more information on the New England municipal system, see New England town.
Corporate changes since 1900
References
Historical United States Census totals for Suffolk County, Massachusetts Wikipedia(Text) CC BY-SA