A friend of mine who grew up in Boston and Rhode Island IM’ed me today about the special election in  Massachusetts today between Martha Coakley and Scott Brown.  “Not sure where all these MA Republicans came from,” he wrote.

Most people — even most Bay Staters — often think that Massachusetts is a blue across the board.  But the truth is that the Bay State has many different shades of blue and purple.

The Almanac of American Politics‘ explains:

“In recent elections, the most heavily Democratic parts of the state have not been the blue-collar wards of Boston (they’re mostly either gentrified or heavily African-American or immigrant), but the university towns such as Cambridge, the Berkshires, and the college-rich Pioneer Valley in the west, and the variously fashionable resort areas such as Martha’s Vineyard, Nantucket, and Provincetown.

“The most heavily Republican (or less Democratic) areas are what political scientist Robert David Sullivan called the ‘Offramps’ — towns near the Interstate 495 ring road and ‘cranberry country’ in Plymouth County and Cape Cod; working-class Worcester County in the center of the state; and high-income Essex County in the northeast.”

Cook Political Report’s Dave Wasserman took it a step further today and explained to the Weekly Standard which areas we should watch:

1) Western Mass – Coakley needs a huge margin out of what I call the “Rachel Maddow Belt” – the Berkshires, where she has roots, and the Pioneer Valley. She probably needs a 5,000 vote lead out of Amherst and high turnout in places like Springfield, Pittsfield, and Northampton.

2) The I-495 Ring – This is Brown’s bread and butter, and he needs to rack up big leads in towns like Haverhill, Dracut, Marlborough, and his home area near Wrentham and Foxborough. These are the places where Mitt Romney broke through to win the governorship in 2002.

3) The Cape and Southeastern Mass – The Kennedy belt. Barnstable and Plymouth Counties are presumably the places where Kennedy’s memory ought to rescue Coakley in the eleventh hour. Brown will probably narrowly win the TOWNS of Plymouth and Barnstable, which are usually bellwethers. If Coakley carries either, she will probably be on her way to winning statewide. If Brown wins both with more than 55%, watch out.

4) The 8th CD – The heart of liberal Massachusetts needs to come out in a big way for Coakley if she is to have a shot. Cambridge should turn out dependably, but will the Boston machine crank out votes at the same rate as other places in the state? Will Capuano’s voters be as enthusiastic about this race after they didn’t get their man?

5) The Catholic south shore – Will working class Democrats stick with their party or defect to Brown? This is the key area to watch in that respect. Brown will probably win Braintree and Weymouth, but the town to watch is Quincy. If Coakley can’t hold onto Quincy, she will probably lose.

6) The ethnic cities – Does Coakley get at least half of Obama’s votes in each of Worcester, Fall River, New Bedford, Lowell, and Lawrence? These are places that will vote Democratic 2-to-1 or more, but where voters need lots of engagement to mobilize.

Lastly, Swing State Project crunches the numbers and shows us what a tie would look like.  For this to happen, Brown would have to win Essex, Hampden, Norfolk and Worcester counties, and take Barnstable and Plymouth by double-digits.  Coakley would have to win Berkshire, Dukes, Franklin, Hampshire, and Suffolk counties by huge margins, and would have to carry Bristol, Middlesex and Nantucket:

Swing State Project: Massachusetts Senate Electoral Map Hypothetical Tie