Recently, the Mayor of Chicopee, Massachusetts, Michael Bissonette, criticized the administration of Governor Deval Patrick for including Worcester County in its definition of "Western Massachusetts" for the purpose of siting a potential "destination resort casino."
Mayor Bissonette reportedly said that "Western Massachusetts" includes only the four western counties - Berkshire, Franklin, Hampden, and Hampshire. In the Mayor's view, Worcester County is really in Central Massachusetts.
The Mayor is not alone in this view. Wikipedia's article on Western Massachusetts also defines the region in this way.
As someone who spends a lot of time in both Central and Western Massachusetts, this observer has thought a great deal on this question.
To begin with, defining Western Massachusetts as the four western counties is arbitrary at best. This would mean that Palmer, where the Mohegans would site their "western" casino, is in the region, but Warren, where the Mashantuckets would site theirs, is not.
This observer can come up with four other defensible definitions of what makes up Western Massachusetts.
A modest variation of the "four county" definition is the "413" definition - everything within the 413 area code is in western Massachusetts - everything outside of it is not. This means that the Worcester County towns of Warren and Hardwick are in Western Massachusetts, but the Franklin County towns of Orange, Warwick, and New Salem are not. This also seems to be a mostly arbitrary definition.
Thinking as broadly as possible, one defensible definition of Western Massachusetts would include all of Worcester County. Springfield and Chicopee have as much in common with Worcester and Fitchburg as they do with Pittsfield and North Adams - and arguably more. (Ask someone from Pittsfield whether Springfield is in Western Massachusetts.)
All of these communities have traditionally been underfunded and underrespected by the powers that be in the state government in Boston. In fact, an artificial political separation of western and central Massachusetts benefits only those who have an interest in a "divide and conquer" approach to the allocation of political and financial power.
From a geographic perspective, all five counties are part of the Appalachian highlands that run from Maine to Georgia - a dramatically different landscape from the coastal region of eastern Massachusetts.
Another narrower definition of Western Massachusetts - but still broader than the typical definition - would place the dividing line at the eastern boundary of the Connecticut River basin. This would place the boundary on a line running roughly from Gardner through Spencer to Sturbridge. Much of western Worcester County - the areas drained by the Quaboag, Swift, Ware, and Millers Rivers - would be considered to be part of Western Massachusetts under this definition.
From a personal psychological perspective, this is a satisfying definition. As one drives west along Route 9 in Spencer - less than ten miles west of Worcester - there is a place just east of the center of town where the landscape opens to a rather long and broad vista. This vista is the beginning of the Quaboag Valley. From a personal perspective, this is where western Massachusetts begins.
An even narrower definition of Western Massachusetts would place the dividing line at the eastern edge of the plain that runs east of the Connecticut River. This line would run from Montague to Amherst to Wilbraham. By this definition, the hills to the east of the line are really part of the Central Massachusetts highlands. Palmer and Shrewsbury share more in common in this regard than Palmer and Chicopee. Driving south on Interstate 91 in Holyoke near the Soldiers Home on a clear day, if one looks slightly to the left, one sees the broad openness of the Connecticut River valley with some substantial hills in the background. These hills are in Monson, Palmer, and Belchertown. By this definition, these hills are where Central Massachusetts begins.
All of the above are what I would consider defensible definitions. Another more elusive definition - one in keeping with a recent TER piece - would define Western Massachusetts as being that part of the state that is not part of Red Sox Nation. This is a less frivolous or trivial definition than it might first appear. Allegiance to the Red Sox is an example of Boston's cultural influence. Where the Red Sox fade, so too does Boston. Unfortunately, this is a harder definition to fix with precision. For the most part, Western Massachusetts would be confined according to this definition to the area west of the Connecticut River.
What is Western Massachusetts, anyway? I guess it depends, but trying to think carefully about definitions is the beginning of clear thinking.