The first country to have adopted time zones was New Zealand, than still part of the British Empire, in the second half of the nineteenth century, or more specifically on November 2 in 1868. It was based on the longitude of 172° 30' East of Greenwich, which is 11 hours and 30 minutes ahead of the GMT.
The answer for this question is: New England
The region of new England was the main target destination for the people who want to seek job opportunity during that time (mostly from Massachusetts)
Not only that, the economic growth in this region also give the people with enough resources to sustain their living so their mortality rate is really low.