Why was the US a magnet for immigrants in the nineteenth and early twentienth centuries?

The United States was a magnet for immigrants in the nineteenth and early twentieth centuries due to its promise of economic opportunity, political freedom, and social mobility. Many sought to escape poverty, famine, and political unrest in their home countries, particularly in Europe. The availability of jobs in rapidly expanding industries and the allure of the American Dream attracted millions. Additionally, the relatively open Immigration policies and the idea of a land of opportunity fueled the desire to start anew in America.