Technology, immigration, and a lack of government regulation of business were some of the forces that changed the economic landscape of the United States in the late nineteenth century. Although the northern United States had begun significant industrialization prior to the Civil War, the US was still largely an agrarian country. After the Civil War, it became an industrial power house and ended the century poised to become the new world power.
Technology drove economic advances in the US. The development of lighter weight steel aided the expansion of the railroads, making it easier to ship goods rapidly all over the United States. Communications improved with the successful implementation of a transatlantic telegraph and the invention of the telephone. The electric light and greater reliance on gas and oil as fuel increased factory productivity. The late nineteenth was driven by a dizzying array of technological innovations.
Immigration from Europe was unlimited in this time period and Europeans flooded into this country. These provided a very low cost labor supply for factories and railroad projects.
Rapid change in an unregulated economic environment allowed the rapid accumulation of wealth. A large labor pool and lack of a minimum wage or any benefits to employees allowed for exploitation. The absence of government inspections meant that the processed food new urban dwellers often relied on was often adulterated with cheap additives, increasing profits. The unregulated environment also gave a few corporations or individuals to opportunities to create monopolies, in which they were the only business providing a certain service or in which they vertically controlled an entire industry. This allowed certain businesses to charge very high prices because consumers and other businesses were dependent on what they provided and had nowhere else to turn. This was also a major factor driving wealth inequality in this period.