In the period of the 1700's and 1800's the people living in New England were able to live on only certain parts of it. The reason for that was the landscape, but also that the railroads and the road systems were still not established, nor the technology was at a level to help shape up the terrain as they would have wanted to.
The central and western part of New England was dominated by high mountains covered with dense forests. The terrain was steep, not suitable for agriculture, and also hard to get to. Big portion of the eastern part of New England, especially the coastal parts were covered with swamps. The swamps were a generator of diseases, and also made the terrain hard to move through.
Because of this, the people were settling on parts in the eastern part of New England were there were no swamps and they had access to the ocean. That enabled them to have an ongoing constant trade with Europe, as well as with the southern colonies, thus they were able to get access to the goods and materials relatively easy.
