America's number one leading import was people. These immigrants that came to America had many reasons to do so, it was cheaper, there was more room and the warfare and overcrowding of Europe. People could afford to buy land in America and have space to own it; the only real problem was actually getting to the New England ports. America's main import of people were from Ireland and Germany, who had their own reasons for coming over.
The potato famine in Ireland was one of the main reasons for the Irish coming over. The potato was the major food crop in Ireland, and a huge blight hit in 1845 and wiped out about half their crops nationwide. Then again in 1850 all of their crops had disappeared, death haunted the Irish land. Even though the Irish were coming to America before the famine, they were overtaken by English rule, so some decided to come to America then.

After arriving in the New England ports, most decided to stay there because they had little money to purchase land after buying their tickets to America. But those who could afford it and were healthy enough would start helping produce the country (i.e. the Erie Canal). The Irish were one of the main labor workers for the Erie Canal it took about 9 years to build which took place in 1817-1825. Those who came from Ireland brought life to many western cities.
The Irish were not the only major immigrants to America; Germans were starting to flood in. In 1854, Germans made up almost half the population of U.S. immigrants. Boundaries were starting to change in Germany and peasants were beginning to refuse to pay their taxes. In 1848 a civil war and revolution in Germany had begun.
There was a small total of only about three thousand political refugees from Germany. Carl Shurz was one to be named. He helped build in the United States the democracy that wasn't possible in Germany. He also organized a rebellion against the German government, he became a lawyer in U.S., he campaigned for Lincoln in 1860, he was a fighting general in Gettysburg, a minister to Spain, senator of Missouri, and he was cabinet secretary of the interior. He was a very well know man though out the country. The Germans brought great career opportunities to the U.S. A major one was the idea of schools, especially physical education. This caused immigrants from all over to come for a new life, and to help produce the country like the Irish and Germans did.