The term Yankee is used a lot, but there isn't much agreement on what it means.
Ask most people in other countries and they'll tell you a Yankee is someone from America.
Ask someone born in the southern U.S. and they'll tell you a Yankee is someone from north of the Mason-Dixon Line.
Ask someone from most of the rest of the country, and they'll say a Yankee is someone from the northeastern part of the U.S.
Ask someone from that part of the country, and they'll likely tell you it's someone from the New England states.
Ask a New Englander, and most likely they'll say it's someone from Maine.
Go to Maine, and they'll tell you it's someone from Down East Maine.
Go to the Down East coastal area and I don't know what they'll say--perhaps that true Yankees come from some small village on the coast. Go there, and I suspect they'll tell you a Yankee is Old Joe down on Fremont Street....
So now you know....