The mountainous New York state as well as separation of NYC (Manhattan) and Brooklyn are both nice touches.
As usual, there are several possible suggestions:
For NYC region:
1) Newark is actually a bit southern than Manhattan, around the same latitude as Brooklyn.
- Maybe move Newark one hex south, and change the original hex to a swamp, to represent the New Jersey Meadowlands (a huge, heavily polluted swamp north of IRL Newark).
2) Judging from the coastline, the 5-supply small city south of NYC is Staten Island+Upper New York Bay. IRL the major ports activities of NYC all happened in the New York Harbor, including Upper Bay and nearby Newark Bay, between Staten Island, Newark and Manhattan. On the other hand, the west end of the Long Island Sound doesn't have large port installations IRL.
- Maybe change this hex to a major 10/12 supply level port, to represent the New York Harbor.
3) One of the biggest USA naval shipyard, the Brooklyn Navy Yard, as the name suggest, is at Brooklyn.
- Maybe add another major port attached to Brooklyn besides the New York Harbor one.
4) Separating NYC and Brooklyn is a nice touch. However I am not sure about having a land&sea hex between NYC and Brooklyn; this looks like Brooklyn is situated deeply inside the Long Island. I understand that, at the current map design, you need a sea hex to access the port in the Long Island Sound, as the Long Island Sound is being soft-blocked by the port of New Haven.
- Then If having two major ports at the south of NYC and Brooklyn (as the suggestions above), you can move Brooklyn one hex west, next to NYC.
5) Related to 4) above - the port of New Haven is currently at a awkward position, as it soft-blocked the Long Island Sound. IRL the Long Island Sound near New Haven is actually the widest section of the Sound. The shape of Long Island Sound is narrow in the west but broad in the east, rather than having a straight coastline. Moreover, the city of New London,
the location of a primary submarine base, is at the eastern end of the Long Island Sound; the sea hexes of the Long Island Sound should also leave space for a port attached to New London.
- Maybe the eastern part of the Long Island can move one hex southward, to leave more space to the Long Island Sound. I also noticed that the Long Island Sound in the current WWI map is more than 1 hex wide (it's a 1-2-1-2 wide shape).
- In addition, there are some forts at the east end of Long Island to protect the Sound as well as New London naval base. Although I am not sure how to represent a naval fort on the map - a fortification with a coastal gun unit?
6) Maybe add West Point between Yonkers and Poughkeepsie, as a fortified town on the Hudson River, in case someone try to cut the supply line north of NYC.
For non-NYC region:
7) Maybe some changes of the coastline can apply to the Lake Ontario in the future (say, in the Ontario episode of the map making), a straight coastline is bit weird.
8) IRL Plattsburgh have
fortifications and
barracks built in the aftermath of War of 1812, later abandoned in the late 19th century as there were no further US-Canada conflicts. In TL-191, the USA and Canada confrontation continues, this town would probably turned into a major US Army installation at USA-Canada border at 1914.
9) Kingston, ON actually didn't have a land connection/crossing with USA; this part of the St. Lawrence River is still pretty wide (the narrow parts are from Ogdensburg to Montreal). The only crossing on the St. Lawrence River between Niagara River and Montreal before WWI was New York and Ottawa Railway's bridge at Cornwall, ON (today's Three Nations Crossing). This railway connects New York state directly with Ottawa, a crucial piece of infrastructure. Maybe the land connection between USA-Canada can be moved at Cornwall.
No conquest without labor.