If the border has indeed shifted south, meaning Sox nation has expanded it is most likely the band-wagon effect of winning the championship. I moved out of Boston at the turn of the century but prior to that was a season ticket holder in the 90's. I can remember on nights I couldn't make it to the game I would literally have trouble giving the tickets away, or I would give them to co-workers etc only to find out later they didn't bother to go. This despite the sox being very competitive at the time. Nowadays I hear getting a ticket is like trying to score celtics tickets in the 80's....Impossible. What's worse is that I hear bandwagoners, I mean fans are naming their dogs "Fenway." Hold on while I clear my keyboard of vomit.

Similarly: where is the border between St. Louis Cardinal and Chicago Cubs fandom? It seems to exist in an east-west line somewhere around Pontiac, about 100 miles south of Chicago... but I'd appreciate other readers' analyses.

Note: The White Sox are not included in this discussion because no one south of Blue Island even knows they exist.

I would put the Cubs/Cards border farther south. Growing up in Decatur, it was pretty evenly split. Champaign is Cubs territory, especially if you count all the students from the Chicago suburbs. Bloomington/Normal is similar. Springfield is clearly Cardinal country. Peoria is Cub territory.

The White Sox are a team???

I grew up in Western Mass which is by any definition Sox territory, but there were always a few loud Yankee bandwagoners. By rule no one can legitimately be a Yankee fan North of Hartford and East of New Haven. I wonder where the line in drawn in the Maritimes between Sox and Jays fans?

I'd say I-91. Those East thereof trend Sox, West trend Yanks.

Whoops, already said in the article. That's what you get for careless reading on a Friday afternoon.

The red sox are the personification of evil.

Kim Jong-Il roots for them.

As a native of Portsmouth, New Hampshire I've always assumed the line was at the Mass/Conn border. I mean, don't folks in Conn. support the Giants and the Jets rather than the Patriots (and I'm talking about the lean years, not the aberrant, joyous years of the recent past)? And, of course, Conn. folks had the Whalers (hiss) instead of the Bruins. I just assumed Conn. was hostile country across the board, and as a child even discussed with friends the possibility of having Conn. officially designated as a non-New England. Anyway, I miss the Whalers . . .

Maybe not great data, but it is data

http://www.commoncensus.org/sports.php

Here in Cali, the great debate is where does Dodgerland end and the Giant's Zone begin. (The Oakland A's are the White Sox of Cali, most interesting to fans in the immediate Oakland area and - lately - economists who've read Moneyball.)

While Burlington, Vermont is squarely in Red Sox territory, we are in close proximity to Yankees fans just across the lake in NY state. Periodically, they make incursions across the border and have to be repulsed by all means necessary, including withholding Ben and Jerry's shipments. Only by denying Yankees fans their supply of Chubby Hubby can we bring them to their kneees...

My memory from growing up in small town Rhode Island in the 1960s was that the dividing line was based on which "old country" your people came from rather than geography. The Italians were typically Yankees fans, probably a DiMaggio thing, and the rest--the Irish, mainly, but also the newer immigrant groups like the Portuguese--were Bosox people.

"I grew up in Western Mass which is by any definition Sox territory, but there were always a few loud Yankee bandwagoners. By rule no one can legitimately be a Yankee fan North of Hartford and East of New Haven. ?"

I disagree, having grown up on the shoreline east of New Haven, towns there are solidly Yankee towns. They are all on the shoreline east/Metro North Rail line, and are dominated by the Local New York News Channels,zero Boston News channels. Old Saybrook is when it starts to change a bit, which makes sense, since it hugs the CT River the true border of Yankee Country and the Red Sox Nation. Even Hartford is still iffy with the Sox, I will concede it to the Nation, but only due to the recent bandwagon effect. There are still plenty of Yankee and old whaler fans than can't stand Boston.

Kevin wins--CT River, imho. Definitely closer to the mark than I-91.