As Western Europe industrialized in the mid-to-late 1700s, the United States remained agrarian with resource processing, gristmills, and sawmills being the main industrial, non-agrarian output. As demand for U.S. resources increased, canals and railroads became important to the economic growth as transportation necessitated and the sparse U.S. population, especially in areas where resources were being extracted such as the Western frontier. The Industrial Revolution was an epoch during the first 100 years of United States history where the economy progressed from manual labor and farm labor to a greater degree of industrialization based on labor. The First Industrial Revolution was marked by shift in labor, where in the United States an outwork system of labor shifted towards a factory system of labor. Throughout this period, which lasted into the mid-19th century much of the U.S. population remained in small scale agriculture.
