Region of the country that has made the sharpest ideological 180

[jocallag]

I think Broward County (Ft Lauderdale-Hollywood) has experienced an extreme shift from being one of the most conservative Republican counties in the 1960s to slightly Democrat in the 1970s and 1980s..as late as 1988 it even voted barely for George H W Bush.
As the older conservatives who made it one of Barry Goldwater's (56%) best large counties have moved or died off, the Jewish senior wave of the mid-1970s made it much more Democrat especially at the local level.
It voted for Carter in 1976 but swung sharply back to Reagan in 1980 as many Jewish voters defected to Anderson and Reagan. In the nineties it became increasingly Democrat voting big for Clinton in both 1992 and 1996.  It was one of the few large counties where Al Gore did better than Clinton due to Lieberman's presence as VP as Jewish voters swung heavily to the Dems.  An increasing Black vote (now above 20% - even larger than neighboring Miami-Dade) will make it a key county for Obama in 2012.

[Ember]

the Appalachian region, particularly West Virginia. the ideological change has already been sharp, but it's only going to become even deeper over the years.

[soniquemd21921]

DeKalb county, GA is pretty interesting.

In 1976 it was Carter's worse county, I believe. He won Georgia with 66% yet he only won 56% in Dekalb.

In 2008,  McCain was the guy who won Georgia, with 52% of the vote, yet he only got 20% of the vote in DeKalb that year.

So the county goes from 10 points more R than the state as a whole, to 32 points more D in 30 years. This is pretty much all due to demographics. The county is over 50% black, so the minority voters make it Democratic. Then, the yuppies, college students at Emory, and researchers at the CDC make it liberal as well.

Goldwater carried De Kalb county as well (57 percent). In 1972 it gave Nixon 77 percent, but by 1984 it gave Reagan just 58 percent.

Another Georgia county that has changed dramatically is Clayton, another Atlanta suburb. It gave Goldwater 64 percent of the vote, Nixon an astonishing 86 percent in '72, and Reagan 73 percent in '84. But the county has seen a tremendous growth of black residents in the last 20 years - Obama received 83 percent of the vote in Clayton.

[All Along The Watchtower]

the Appalachian region, particularly West Virginia. the ideological change has already been sharp, but it's only going to become even deeper over the years.

Not really an ideological change going on there. It's always been socially conservative/economically populist (for lack of a better term). But the lack of the latter in the modern Democratic Party and the presence of the former in the modern Republican Party means...yeah.