Quickly glancing over the county maps, it seems that the only New England counties where McKinley was held below 60% were Suffolk, MA, and either Hartford or New Haven, CT (maps disagree and I'm not shelling out for an Atlas membership), which would seem to track with general Democratic support, albeit diminished by the unique circumstances of this election, among industrial laborers and white ethnics. A few other quirks of the county map make me wonder if there was elevated support among French-Canadians as well, but again I lack the will and resources to dig deep enough.
This seems as good a place as any to point this out: the county results for CT in pre-1900 presidential races are completely mixed-up. (In the most blatant example, I highly doubt New Haven County cast the second-fewest votes in the state in 1896.) The
old state Manuals have the correct results; can an admin make the changes? This is especially problematic because Wikipedia is displaying
wrongly colored maps based on the incorrect Atlas data.