Westward movement, the populating by Europeans of the land within the continental boundaries of the mainland United States, a process that began shortly after the first colonial settlements were established along the Atlantic coast. The first British settlers in the New World stayed close to the Atlantic, their lifeline to needed supplies from England. By the 1630s, however, Massachusetts Bay colonists were pushing into the Connecticut River valley. Resistance from the French and Native Americans slowed their movement westward, yet by the 1750s northern American colonists had occupied most of New England.