At the beginning of the nineteenth century most American families had come from Britain, Germany and Scandinavia, and they were farmers or businesspeople. But soon that began to change.
Factories were built and cities grew; poor people arrived from other countries, hoping to find work. Between 1840 and the end of the century, about five million people came from Ireland alone. Another five million immigrants came from Italy, and millions more from Russia, Poland and other countries of Eastern Europe, hoping to find jobs and freedom. America kept an 'open door' until 1924 and about 27 million people arrived between 1880 and 1930. They were often poor, had different religions, and had not been to school for very long; there was a lot of prejudice against them.
The Chinese immigrants in the West also met with prejudice. Many people came to live in California after gold was found there in 1848, and among them were 300,000 Chinese. Many of the Chinese stayed to work building the new railways. Like black people and Native Americans, the Chinese had no civil rights and after 1882, they were no longer allowed to enter the USA.
The Irish, Italians and Eastern Europeans usually stayed in the big cities of the East or the Mid-West, like New York, Boston or Chicago, and worked in the factories. Although most of them learned English and became Americans, they also wanted to keep their own way of life. So in many cities you can find places known as Little Italy or Chinatown, where the restaurants have Italian or Chinese food. This is all part of what makes America an interesting and exciting country.