About 40 miles, if you mean the ones in New York.
I'm not positive that it is the closest, but I know that Bethany beach, de is fairly close. I believe it's only 5 hours away.
45.04 miles (72.49 kilometres)
2,483.75 kilometres (1,543.34 miles)
The distance is about 3 miles from West Yellowstone, Montana to the Wyoming border.