What area is part of the Mid Atlantic region but is not a state?

i need help on it I'm at home doing homework

The largest Mid-Atlantic state is New York, with an area of 54,555 mi2 (141,299 km2).

Yes, it is. Some people consider it a Southeastern state though.

they are Pennsylvania, Delaware, Maryland, New York, and New Jersey.

there are 5 including Washington D.C.