Pronunciation of 'aunt' in the US

I was under the impression that all Americans pronounced aunt like the insect, ant (/ænt/), or relatively similar sounding variants such as the southern aint (/eɪnt/). According to both Webster and ODO, some Americans pronounce it as ah-nt (/änt/, /ɑnt/, or /ɔnt/) which is pretty close to the British ah-nt (/ɑ(:)nt/). Webster offers a similar alternative for the contraction, can't.

Who are these Americans who favour the British pronunciation?

Solution 1:

The Northeast.

This US dialect splatter chart shows that just over 75% of Americans pronounce aunt and ant (the bug) the same. It’s broken down further, but the ~ohnt pronunciation is primarily from the Northeast.

Solution 2:

I've found two groups of people who pronounce aunt that way. First, many New Englanders (people from the Connecticut, Rhode Island, Massachusetts, Vermont, New Hampshire, and Maine) do so. Also, many African-Americans from the East Coast also pronounce aunt that way, whether or not they are from New England.

Solution 3:

This may not be the answer; however, I just wanted to add this.

I have always thought why the digraph <au> in aunt has a TRAP vowel variant, whereas the same digraph receives LOT/THOUGHT vowels in other set of words. After reading Christopher Upward's The History of English Spelling, I have found an answer.

Spelling change and pronunciation change

<aun> > <an>

aunswar > answer
haunde > hand
daunce > dance
braunche > branch
avauntage > advantage

<an> > <aun>

hanch > haunch
vant > vaunt

No spelling change, but variant pronunciations

aunt 

Variant spellings

gauntlet vs gantlet
staunch vs stanch
gauntry vs gantry

Solution 4:

It's a matter how you treat diphthongs in your vernacular. I'm from Virginia and on average we say the AU not the AN for pronouncing our uncles wife. The same can be said for daughter, which is Dawter, not Dwater or Dotter.