Brookline is a town in Norfolk County, Massachusetts, United States, and part of the Boston metropolitan area. Brookline borders six of Boston's neighborhoods: Brighton, Allston, Fenway–Kenmore, Mission Hill, Jamaica Plain, and West Roxbury. The city of Newton lies to the west of Brookline. Brookline was first settled in 1638 as a hamlet in Boston, known as Muddy River; it was incorporated as a separate town in 1705.

The town is the basic unit of local government and local division of state authority in the six New England states. Most other U.S. states lack a direct counterpart to the New England town. New England towns overlay the entire area of a state, similar to civil townships in other states where they exist, but they are fully functioning municipal corporations, possessing powers similar to cities and counties in other states. New Jersey's system of equally powerful townships, boroughs, towns, and cities is the system which is most similar to that of New England. New England towns are often governed by a town meeting, an assembly of eligible town residents. The great majority of municipal corporations in New England are based on the town model; there, statutory forms based on the concept of a compact populated place are uncommon, though elsewhere in the U.S. they are prevalent. County government in New England states is typically weak at best, and in some states nonexistent. Connecticut, for example, has no county governments, nor does Rhode Island. Both of those states retain counties only as geographic subdivisions with no governmental authority, while Massachusetts has abolished eight of fourteen county governments so far. Counties serve mostly as dividing lines for the states' judicial systems and some other state services in the southern New England states, while providing varying services in the more sparsely populated three northern New England states.