What was the period of industrialization?

Industrialization was the rapid development of factories, mass production, mechanized manufacturing, and large industrial corporations in the United States between roughly 1820 and 1920, transforming the country from a primarily agricultural society into the world's largest industrial economy by the early twentieth century.

The first wave of American industrialization began in New England in the early nineteenth century. Samuel Slater established the first successful textile mill at Pawtucket, Rhode Island in 1790. The Boston Manufacturing Company opened the integrated cotton mill at Waltham, Massachusetts in 1814, the first to combine spinning, weaving, and finishing under one roof. The Lowell mill complex in Massachusetts opened in 1823 employing thousands of young women in textile production.

Iron and steel production expanded with the introduction of anthracite coal in Pennsylvania ironworks in the 1830s. Steamboats spread on western rivers after Robert Fulton's pioneering work in 1807.

The second and far larger wave of industrialization followed the Civil War from 1865 to 1920, sometimes called the Second Industrial Revolution. The Bessemer process for cheap steel, introduced commercially in the United States by Andrew Carnegie at the Edgar Thomson Works in Pittsburgh in 1875, transformed construction, transportation, and machinery. Iron production rose from about 800,000 tons in 1860 to about 2.7 million tons in 1880, and steel production grew from negligible amounts to about 28 million tons by 1900, making the United States the world's largest steel producer.

Petroleum extraction began at Titusville, Pennsylvania on August 27, 1859 with Edwin Drake's first successful oil well. John D. Rockefeller's Standard Oil Company, founded in 1870, controlled about 90 percent of American oil refining by 1880.

Electrification transformed manufacturing after Thomas Edison's first practical incandescent light bulb in 1879 and the first commercial power station at Pearl Street in New York City on September 4, 1882. Henry Ford's introduction of the moving assembly line at his Highland Park, Michigan factory in 1913 reduced the time to assemble a Model T from 12 hours to 93 minutes.

Industrial production increased fourteenfold between 1860 and 1900. The number of factory workers grew from about 1.3 million in 1860 to about 8 million in 1910. Industries included textiles, steel, machinery, food processing, oil refining, electrical equipment, automobiles, and chemicals. By 1900 the United States had surpassed Britain to become the world's leading industrial power.

Industrialization concentrated wealth in the hands of industrialists called Robber Barons or, more sympathetically, Captains of Industry, including Andrew Carnegie, John D. Rockefeller, J.P. Morgan, Cornelius Vanderbilt, and Andrew Mellon. It also produced labor unrest, with major strikes including the Great Railroad Strike of 1877, the Haymarket Affair of 1886, the Homestead Strike of 1892, and the Pullman Strike of 1894.