In the decades following the Civil War, the United States emerged as an industrial giant. Old industries expanded and many new ones, including petroleum refining, steel manufacturing, and electrical power, emerged. Railroads expanded significantly, bringing even remote parts of the country into a national market economy.

Industrial growth transformed American society. It produced a new class of wealthy industrialists and a prosperous middle class. It also produced a vastly expanded blue collar working class. The labor force that made industrialization possible was made up of millions of newly arrived immigrants and even larger numbers of migrants from rural areas. American society became more diverse than ever before.

Not everyone shared in the economic prosperity of this period. Many workers were typically unemployed at least part of the year, and their wages were relatively low when they did work. This situation led many workers to support and join labor unions. Meanwhile, farmers also faced hard times as technology and increasing production led to more competition and falling prices for farm products. Hard times on farms led many young people to move to the city in search of better job opportunities.

They were willing to use military force to keep the South in the Union. Even Southerners who owned no slaves opposed threatened Federal coercion. The result was a costly and bloody civil war. Almost as many Americans were killed in the Civil War as in all the nation's other wars combined.

Not everyone shared in the economic prosperity of this period. Many workers were typically unemployed at least part of the year, and their wages were relatively low when they did work. This situation led many workers to support and join labor unions. Meanwhile, farmers also faced hard times as technology and increasing production led to more competition and falling prices for farm products. Hard times on farms led many young people to move to the city in search of better job opportunities.

Americans who were born in the 1840s and 1850s would experience enormous changes in their lifetimes. Some of these changes resulted from a sweeping technological revolution. Their major source of light, for example, would change from candles, to kerosene lamps, and then to electric light bulbs. They would see their transportation evolve from walking and horse power to steam-powered locomotives, to electric trolley cars, to gasoline-powered automobiles. Born into a society in which the vast majority of people were involved in agriculture, they experienced an industrial revolution that radically changed the ways millions of people worked and where they lived. They would experience the migration of millions of people from rural America to the nation's rapidly growing cities.