New York grew as an economic center, first as a result of Alexander Hamilton's policies and practices as the first Secretary of the Treasury and, later, with the opening of the Erie Canal in 1825, which connected the Atlantic port to the vast agricultural markets of the Midwestern United States and Canada. By 1810, New York City, then confined to Manhattan, had surpassed Philadelphia as the largest city in the United States. The Commissioners' Plan of 1811 laid out the island of Manhattan in its familiar grid plan.