About 35 years ago, I was visiting Toronto and saw my first black squirrels. They were very numerous there. I see that some carrying the melanistic gene must have made their way to NY. I used to see them in my Queens neighborhood, with normal grey squirrels in the same litter.
Teenagers call them squiggers.
Omaha, Nebraska - used to just see them in the Peony Park area or slightly north of Dodge and east of about 84th.
We now have at least one in our immediate neighborhood which is in suburbia, to the southwest a good 10+ miles. I guess it is some type of diversity or integration plan.
In my home town of Goshen Indiana somebody imported black squirrels from Canada and they set up quite a community there.