Located in the western part of Massachusetts, Western Massachusetts consists of the following counties:
Berkshire, Franklin, Hampshire and Hampden counties, in the year 2000 collectively had 814,967 residents, a population greater than that of any one of the six smallest U.S. states. The population amounted to approximately 12.84% of the 2000 population of the entire state of Massachusetts, which was 6,349,097. Its average population density is 293.07 inhabitants per square mile (113.16/km²), compared to 422.34/km² (1,093.87/sq mi) for the rest of Massachusetts, and 312.68/km² (809.83/sq mi) for the state as a whole.
Western Massachusetts’ population is concentrated in the cities and suburbs along the Connecticut River in an urban axis surrounding Springfield that is contiguous with greater Hartford, Connecticut (i.e. the Knowledge Corridor.) A secondary population concentration exists in the Housatonic-Hoosic valley due to the industrial heritage of Pittsfield and North Adams, and the development of tourism throughout that valley. This far-western zone is linked to New York City and Albany, New York more than with the rest of Massachusetts, however both populated zones are ultimately part of the northeast megalopolis. The rest of Western Massachusetts is lightly populated, particularly the Hilltowns where densities below 50 persons per square mile (20 per km2) are the rule.