Over the past few days I've mentioned "The Yankee Migration" but I'm not really certain that most people know what took place or what the term means.
One enlightening resource is William Cooper's Town: Power and Persuasion on the Frontier of the Early American Republic by Alan Taylor. Winner of the 1996 Pulitzer Prize for History, this book presents the reader with a good representation of upstate New York when it was still considered "frontier country." William Cooper, the founder of Cooperstown and father of James Fenimore Cooper, was one of many land speculators who bought up large tracts of northern New York. As New England became more crowded and most farmland was already bought up and/or overworked, residents headed westward across Massachusetts to Albany and then along the Mohawk River and what would later be the Erie Canal. Cooper was ready to sell them fertile land and made a pretty profit too.
My Crandall and Austin branches were such Yankee migrants, especially the Austins. With Robert Austin's birth in North Kingstown, Rhode Island in 1638, the descendants of Robert would appear in Lewis county beginning in the early 1800s. By the end of the 19th century, not only would they inhabit parts of Lewis, Saint Lawrence, Oneida and Jefferson counties, but move even farther west to parts of Ohio, Illinois and Wisconsin. A great resource for this migratory pattern is Roots and Routes - complete with a great visual of the actual routes taken by the settlers.
If you have upstate New York ancestors I bet they were most likely part of The Yankee Migration.