Easily the Middle Colonies, and the higher birth rate and lower infant mortality from this region shows this. The Northeast had poorer soils and a colder climate, in addition to more hostile natives. It is truly a wonder that the Pilgrims survived at all! The Southern colonies, while boasting a warmer climate, had to contend with the mosquito which brought malaria and yellow fever. Of course this was also a problem in England--Charles Mann in the book 1493 even states that many of the mosquito problems faced in the Southern colonies and Caribbean were brought over from the Old World to the New in the holds of English ships. The Southern colonies also suffered from poor placement and hostile natives. The settlement at Jamestown was initially located next to a slow-moving portion of the James River, a natural mosquito breeding ground. The Middle Colonies were ideal. The soil was great for growing things; to this day New Jersey is still called the Garden State. The colonists got along well with the native populations (for the most part) and the climate allowed for a long growing season. Until America expanded further west, this region was considered America's breadbasket.