The United States had always been a nation of immigrants. Between 1800 and 1860, just about six million immigrants came to America. The vast majority of them came from countries in northern and western Europe, such as Ireland, Germany, and Scotland.
After the Civil War this number quadrupled with 25 million people arriving on the shores of the United States from 1865 to 1915. While the majority of immigrants still came from northern and western Europe, an increasing number came from countries in eastern and southern Europe, such as Greece, Italy, Russia, and Poland. These new immigrants often settled in cities and provided the necessary labor in the factories.