What's with the D cluster in far northwestern CT?
Those towns have wealthy New York City residents who either have vacation/weekend homes or move there when they retire. They are fiscally conservative but socially liberal. There are lots of places in NY and CT that voted for Bush in '92, Dole in '96, some even Bush in 2000 but have taken a hard left turn in the last 3 elections at the Presidential level. In 2004 Kerry lost Litchfield County because of a bigger swing to Bush in the larger suburban/working class towns like Torrington, New Milford and Watertown. Those 3 towns together have about half the county's population. The strongly Democratic towns are very tiny and were outvoted.
Thats a great map.
I wonder why Plymouth and Worcester Counties are the most Republican in Massachusetts generally. Plymouth doesn't have the working class areas that Bristol does, but that doesn't explain all of it. If its a wealth thing, then Barnstable and Dukes (Martha's Vineyard) would be more GOP than Plymouth I think.