What place in the US is the farthest east that you can go?
Quoddy Head State Park, Maine is the farthest east on the US mainland.
St. Croix in the US Virgin Islands is further east.
Maine is the easternmost state in the United States of America. Its coordinates are 45 degrees five minutes North 69 degrees West. Regionally, it's the northern and eastern most state of New England.
Of course, if you are talking about the lower, or contiguous 48 states, the answer changes, but this is not part of the question. I think the Pochnoi Point argument is more than a mere technicality. If, for example, we had not moved the International Date Line in order to keep all of Alaska on the eastern side of it, then Pochnoi Point would unambiguously be the place where sunrise of a new day would first fall upon the US. But moving the Date Line for the sake of time continuity does not change what hemisphere a body of land belongs to.